The big hit made a winner of Eric Stults (7-3), who allowed two runs on seven hits through six innings. Stults struck out three and walked one.
Huston Street secured the triumph with his 22nd save of the year.
Everth Cabrera went 4-for-4 with two stolen bases and Mark Kotsay contributed a pinch-hit homer for the Padres, who avoided a three-game sweep.
Giants reliever Clay Hensley (4-4) was the losers after the Padres reached him for two runs on two hits and two walks in just 1/3 an inning.
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