Robb Nen blew a save in his first game against his former club, but teammate Rich Aurilia homered to ignite a six-run 10th inning and San Francisco beat the Marlins 8-2 Tuesday night.
Aurilia, who entered as part of a double switch in the ninth, led off the 10th with his third homer, all in the past three games. It came off Vic Darensbourg.
Jeff Kent's run-scoring double off Jay Powell made it 4-2, and J.T. Snow added a three-run double.
Nen, traded in November as part of Florida's payroll purge, failed to hold a 2-0 lead. He loaded the bases with no outs in the ninth, and Kent's error at second allowed two runs to score.
But Nen pitched a perfect 10th to complete a three-hitter.
The Marlins' rally before another small crowd prevented Orel Hershiser from getting his first NL victory since 1994. Hershiser, pounded twice by Florida while pitching for Cleveland in last year's World Series, allowed only two hits in six innings.
The 40-year-old also singled, stole a base and scored the Giants' second run in the fifth. He left as a precaution because of back spasms in the seventh.
The first two games of the series have drawn the two smallest home crowds in the Marlins' six-year history. Tuesday's attendance of 12,975 was a slight improvement on Monday's record low of 12,806.
Hershiser dueled with 22-year-old rookie Brian Meadows, who allowed just four hits and two runs in eight innings and had a season-high eight strikeouts.
San Francisco's third consecutive win made Dusty Baker the second San Francisco manager to reach 400 victories. He improved to 400-377 in five years and trails only Roger Craig, who won 586 games with San Francisco.
ROCKIES 6, PHILLIES 1: Darryl Kile left with a bruised kneecap after pitching five shutout innings for visiting Colorado.
Mark Lewis' grounder up the middle ricocheted off Kile's right knee to start the fifth. Kile, who has won three straight starts, finished the inning before limping off the field. The Rockies, who have won four of five, said Kile had a bruised right kneecap.
Dante Bichette had three RBI, Todd Helton and Larry Walker homered, and eight different Rockies hit doubles.
Kile limited the Phillies to four hits, striking out two and walking two.