SECURITIES & EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             ----------------------

                                  SCHEDULE 13G
                                 (Rule 13d-102)

             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED
                              PURSUANT TO 13d-2(b)

                               (Amendment No. __)*

                          UNISOURCE ENERGY CORPORATION
                                (Name of Issuer)

                           Common Stock, No Par Value
                         (Title of Class of Securities)

                                    909205106
                                 (CUSIP Number)

                                 August 9, 2005
             (Date of event which requires filing of this statement)


     Check the appropriate box to designate the rule pursuant to which this
Schedule 13G is filed:

     [ ]  Rule 13d-1(b)
     [X]  Rule 13d-1(c)
     [ ]  Rule 13d-1(d)


                                                         (Page 1 of 13 Pages)
---------------
     *The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act
of 1934 ("Act") or otherwise subject to the liabilities of that section of the
Act but shall be subject to all other provisions of the Act (however, see the
Notes).




CUSIP No. 909205106                      13G             Page 2 of 12 Pages

-----------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS 
            I.R.S. IDENTIFICATION NO. 
            OF ABOVE PERSONS (ENTITIES ONLY)
                              SAB CAPITAL PARTNERS, L.P.
-----------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                  (a)  [X]
                                                                  (b)  [ ]
-----------------------------------------------------------------------------
     (3)    SEC USE ONLY
-----------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION 
                                              Delaware
-----------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                                                 -0-
SHARES         --------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                                                 1,137,061
OWNED BY       --------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                                                 -0-
REPORTING      --------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                                                 1,137,061
-----------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED 
            BY EACH REPORTING PERSON
                                                 1,137,061
-----------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                       [ ]
-----------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED 
            BY AMOUNT IN ROW (9)
                                                 3.3%
-----------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON ** 
                                                   PN
-----------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 909205106                      13G             Page 3 of 12 Pages

-----------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS 
            I.R.S. IDENTIFICATION NO. 
            OF ABOVE PERSONS (ENTITIES ONLY)
                              SAB CAPITAL PARTNERS II, L.P.
-----------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                  (a)  [X]
                                                                  (b)  [ ]
-----------------------------------------------------------------------------
     (3)    SEC USE ONLY
-----------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION 
                                              Delaware
-----------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                                                 -0-
SHARES         --------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                                                 21,473
OWNED BY       --------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                                                 -0-
REPORTING      --------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                                                 21,473
-----------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED 
            BY EACH REPORTING PERSON
                                                 21,473
-----------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                       [ ]
-----------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED 
            BY AMOUNT IN ROW (9)
                                                 0.1%
-----------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON ** 
                                                   PN
-----------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 909205106                      13G             Page 4 of 12 Pages

-----------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS 
            I.R.S. IDENTIFICATION NO. 
            OF ABOVE PERSONS (ENTITIES ONLY)
                              SAB OVERSEAS MASTER FUND, L.P.
-----------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                  (a)  [X]
                                                                  (b)  [ ]
-----------------------------------------------------------------------------
     (3)    SEC USE ONLY
-----------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION 
                                              Delaware
-----------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                                                 -0-
SHARES         --------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                                                 1,231,766
OWNED BY       --------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                                                 -0-
REPORTING      --------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                                                 1,231,766
-----------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED 
            BY EACH REPORTING PERSON
                                                 1,231,766
-----------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                       [ ]
-----------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED 
            BY AMOUNT IN ROW (9)
                                                 3.5%
-----------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON ** 
                                                   PN
-----------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 909205106                      13G             Page 5 of 12 Pages

-----------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS 
            I.R.S. IDENTIFICATION NO. 
            OF ABOVE PERSONS (ENTITIES ONLY)
                              SAB CAPITAL ADVISORS, L.L.C.
-----------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                  (a)  [X]
                                                                  (b)  [ ]
-----------------------------------------------------------------------------
     (3)    SEC USE ONLY
-----------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION 
                                              Delaware
-----------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                                                 -0-
SHARES         --------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                                                 2,390,300
OWNED BY       --------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                                                 -0-
REPORTING      --------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                                                 2,390,300
-----------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED 
            BY EACH REPORTING PERSON
                                                 2,390,300
-----------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                       [ ]
-----------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED 
            BY AMOUNT IN ROW (9)
                                                 6.9%
-----------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON ** 
                                                   00
-----------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!



CUSIP No. 909205106                      13G             Page 6 of 12 Pages

-----------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS 
            I.R.S. IDENTIFICATION NO. 
            OF ABOVE PERSONS (ENTITIES ONLY)
                                                SCOTT A BOMMER
-----------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                  (a)  [X]
                                                                  (b)  [ ]
-----------------------------------------------------------------------------
     (3)    SEC USE ONLY
-----------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
                                              United States of America
-----------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                                                 -0-
SHARES         --------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                                                 2,390,300
OWNED BY       --------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                                                 -0-
REPORTING      --------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                                                 2,390,300
-----------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED 
            BY EACH REPORTING PERSON
                                                 2,390,300
-----------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                       [ ]
-----------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED 
            BY AMOUNT IN ROW (9)
                                                 6.9%
-----------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON ** 
                                                   IN
-----------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 909205106                      13G             Page 7 of 12 Pages

Item 1(a).     Name of Issuer:

     The name of the issuer is UNISOURCE ENERGY CORPORATION (the "Company").

Item 1(b).     Address of Issuer's Principal Executive Offices:

     The Company's principal executive office is located at One South Church
Avenue, Suite 100, Tucson, AZ 85701

Item 2(a).     Name of Person Filing:

     This statement is filed by:

            (i)   SAB Capital Partners, L.P., a Delaware limited partnership
                  ("SAB"), with respect to shares of Common Stock (as defined in
                  Item 2(d) below) directly owned by it;

            (ii)  SAB Capital Partners II, L.P., a Delaware limited partnership
                  ("SAB II", and together with SAB, the "Domestic
                  Partnerships"), with respect to shares of Common Stock (as
                  defined in Item 2(d) below) directly owned by it;

           (iii)  SAB Overseas Master Fund, L.P., a Cayman Islands exempted
                  limited partnership (the "Master Fund"), with respect to
                  shares of Common Stock (as defined in Item 2(d) below)
                  directly owned by it;

            (iv)  SAB Capital Advisors, L.L.C., a Delaware Limited Liability
                  Company (the "General Partner"), which serves as the general
                  partner of each of the Domestic Partnerships and the Master
                  Fund, with respect to shares of Common Stock (as defined in
                  Item 2(d) below) directly owned by each of the Partnerships
                  and the Master Fund;

             (v)  Mr. Scott A. Bommer ("Mr. Bommer"), who serves as the managing
                  member of the General Partner with respect to shares of Common
                  Stock directly owned by the Partnerships and the Master Fund.

     The Domestic Partnerships, the Master Fund, the General Partner, and Mr.
Bommer are hereinafter sometimes collectively referred to as the "Reporting
Persons." Any disclosures herein with respect to persons other than the
Reporting Persons are made on information and belief after making inquiry to the
appropriate party.




CUSIP No. 909205106                      13G             Page 8 of 12 Pages

Item 2(b).     Address of Principal Business Office or, if None, Residence:

     The address of the business office of each of the Reporting Persons is 
712 Fifth Avenue, 42nd Floor, New York, N.Y. 10019.

Item 2(c).     Citizenship:

     Each of the Domestic Partnerships and the General Partner, is organized
under the laws of the State of Delaware. The Master Fund is an exempted limited
partnership organized under the laws of the Cayman Islands. Mr. Bommer is a
citizen of the United States of America.

Item 2(d).     Title of Class of Securities:

     Common Stock, No Par Value (the "Common Stock")

Item 2(e).  CUSIP Number:

     909205106

Item 3. If this statement is filed pursuant to Rules 13d-1(b) or 13d-2(b) or
(c), check whether the person filing is a:

          (a) [ ] Broker or dealer registered under Section 15 of the Act,

          (b) [ ] Bank as defined in Section 3(a)(6) of the Act,

          (c) [ ] Insurance Company as defined in Section 3(a)(19) of the Act,

          (d) [ ] Investment Company registered under Section 8 of the
                  Investment Company Act of 1940,

          (e) [ ] Investment Adviser in accordance with Rule 13d-1(b)(1)(ii)(E),

          (f) [ ] Employee Benefit Plan or Endowment Fund in accordance with 
                  Rule 13d-1(b)(1)(ii)(F),

          (g) [ ] Parent Holding Company or control person in accordance with 
                  Rule 13d-1(b)(1)(ii)(G),

          (h) [ ] Savings Association as defined in Section 3(b) of the Federal 
                  Deposit Insurance Act,

          (i) [ ] Church Plan that is excluded from the definition of an
                  investment company under Section 3(c)(14) of the Investment
                  Company Act of 1940,

          (j) [ ] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

If this statement is filed pursuant to 13d-1(c), check this box:  [x]




CUSIP No. 909205106                      13G            Page 9 of 12 Pages

Item 4.   Ownership.

     A.   SAB Capital Partners, L.P. 
            (a) Amount beneficially owned: 1,137,061
            (b) Percent of class: 3.3%
                The percentages used herein and in the rest of this Schedule 13G
                are calculated based upon the 34,706,932 shares of Common Stock
                issued and outstanding on August 4, 2005, as reflected in the
                Company's Form 10Q for the Quarterly period ended June 30, 2005.
            (c) Number of shares as to which such person has: 
                (i) Sole power to vote or direct the vote: -0- 
                (ii) Shared power to vote or direct the vote: 1,137,061
                (iii) Sole power to dispose or direct the disposition: -0- 
                (iv) Shared power to dispose or direct the 
                     disposition:  1,137,061

     B.   SAB Capital Partners II, L.P. 
            (a) Amount beneficially owned: 21,473
            (b) Percent of class: 0.1% 
            (c) Number of shares as to which such person has:
                (i) Sole power to vote or direct the vote: -0- 
                (ii) Shared power to vote or direct the vote: 21,473
                (iii) Sole power to dispose or direct the disposition: -0- 
                (iv) Shared power to dispose or direct the 
                     disposition:  21,473

     C.   SAB Overseas Master Fund, L.P. 
            (a) Amount beneficially owned: 1,231,766
            (b) Percent of class: 3.5% 
            (c) Number of shares as to which such person has:
                (i) Sole power to vote or direct the vote: -0- 
                (ii) Shared power to vote or direct the vote: 1,231,766
                (iii) Sole power to dispose or direct the disposition: -0- 
                (iv) Shared power to dispose or direct the 
                     disposition:  1,231,766

     D.   SAB Capital Advisors, L.L.C. 
            (a) Amount beneficially owned: 2,390,300
            (b) Percent of class: 6.9% 
            (c) Number of shares as to which such person has:
                (i) Sole power to vote or direct the vote: -0- 
                (ii) Shared power to vote or direct the vote: 2,390,300
                (iii) Sole power to dispose or direct the disposition: -0- 
                (iv) Shared power to dispose or direct the 
                     disposition:  2,390,300




CUSIP No. 909205106                      13G            Page 10 of 12 Pages

     E. Scott A. Bommer
            (a) Amount beneficially owned: 2,390,300
            (b) Percent of class: 6.9%
            (c) Number of shares as to which such person has:
                (i) Sole power to vote or direct the vote: -0- 
                (ii) Shared power to vote or direct the vote: 2,390,300
                (iii) Sole power to dispose or direct the disposition: -0- 
                (iv) Shared power to dispose or direct the
                     disposition:  2,390,300

Item 5.     Ownership of Five Percent or Less of a Class.

     Not applicable.

Item 6.     Ownership of More than Five Percent on Behalf of Another Person.

     Not applicable.

Item 7.     Identification and Classification of the Subsidiary Which Acquired
the Security Being Reported on by the Parent Holding Company.

     Not applicable.

Item 8.  Identification and Classification of Members of the Group.

     See Item 2.

Item 9.  Notice of Dissolution of Group.

     Not applicable.




CUSIP No. 909205106                      13G            Page 11 of 12 Pages

Item 10.  Certification.

     Each of the Reporting Persons hereby makes the following certification:

          By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.


                                    SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


DATED:  August 19, 2005


                                  /S/ Scott A Bommer
                                  -------------------------------------
                                  Scott A Bommer,
                                  individually and as managing member of
                                  (a) SAB Capital Advisors, L.L.C.,
                                  for itself and as the general partner of
                                  (i) SAB Capital Partners, L.P. and
                                  (ii) SAB Capital Partners II, L.P.; and
                                  (iii) SAB Overseas Master Fund, L.P.




CUSIP No. 909205106                  13G               Page 12 of 12 Pages

                                    EXHIBIT 1

                           JOINT ACQUISITION STATEMENT
                            PURSUANT TO RULE 13d-1(k)


     The undersigned acknowledge and agree that the foregoing statement on
Schedule 13G, is filed on behalf of each of the undersigned and that all
subsequent amendments to this statement on Schedule 13G, shall be filed on
behalf of each of the undersigned without the necessity of filing additional
joint acquisition statements. The undersigned acknowledge that each shall be
responsible for the timely filing of such amendments, and for the completeness
and accuracy of the information concerning him or it contained therein, but
shall not be responsible for the completeness and accuracy of the information
concerning the others, except to the extent that he or it knows or has reason to
believe that such information is inaccurate.


DATED:  August 19, 2005


                                  /S/ Scott A Bommer
                                  -------------------------------------
                                  Scott A Bommer,
                                  individually and as managing member of
                                  (a) SAB Capital Advisors, L.L.C.,
                                  for itself and as the general partner of
                                  (i) SAB Capital Partners, L.P. and
                                  (ii) SAB Capital Partners II, L.P.; and
                                  (iii) SAB Overseas Master Fund, L.P.