Greg Vaughn homered for the third time in two games and Ken Caminiti and Steve Finley also connected for San Diego. The only other time the Padres won 11 in a row was April 14-27, 1982.
Andy Ashby (10-4) gave up five runs and six hits in 7 2/3 innings for his fifth victory in a row, a career-high. He struck out three and walked three in moving into a tie with Atlanta's Greg Maddux for the NL lead in wins.
San Diego improved to 6-1 against San Francisco, including five wins in eight days. The Padres equaled a club record by going 23 games above .500 (48-25) and opening a 5 1/2-game lead over the second-place Giants in the NL West.
The Padres' winning streak coincides with one of Tony Gwynn's biggest slumps. The eight-time NL batting champion was hitless in five at-bats and is hitless in his last 14 at-bats, matching a career low. Gwynn also had a string of 14 hitless at-bats May 12-16, 1993.
Danny Darwin (6-5) went 5 2/3 innings, giving up six runs on seven hits, including both homers. After San Francisco closed to 6-4 on Charlie Hayes' homer in the sixth, the Padres added runs in the eighth on a wild pitch by reliever John Johnston and Carlos Hernandez's second RBI single of the game.
San Diego broke a 3-3 tie with three runs in the sixth on two-out hits by Hernandez and Chris Gomez. Darwin issued one-out walks to Ken Caminiti and Vaughn, and one out later, Hernandez blooped a run-scoring single to right, finishing Darwin. Julian Tavarez relieved and gave up a two-run double to Gomez.
The Padres opened a 3-0 lead. Finley connected in the first for his fifth homer, Vaughn homered to start the second and Finley added an RBI double in the third.
The Giants got a run in the third on Brent Mayne's RBI groundout.
San Francisco pulled into a tie with two runs in the fourth, an inning keyed by Mueller's fly ball to left that dropped for a double when Vaughn lost it in the lights.
Caminiti homered in the ninth off Jim Poole for his 10th of the season.