By MATT BECKER
(AP) -- The San Diego Padres struggled in the opener in San Francisco against Ryan Vogelsong, the owner of the NL's lowest home ERA.
They might not have much better luck against Madison Bumgarner, who has been nearly as tough to score on at AT&T Park.
Bumgarner looks to win his fifth straight in San Francisco and help the NL West-leading Giants continue their impressive surge since the All-Star break Tuesday night against the Padres.
San Francisco (54-42) opened a 10-game homestand by beating San Diego 7-1 on Monday to maintain its 1 1/2-game lead over Los Angeles. Buster Posey hit a three-run homer - one of his three hits - and finished with four RBIs, while Ryan Theriot and Melky Cabrera also had three hits apiece. It was the fifth straight win at AT&T Park for the Giants, who are tied for the majors' second-best home record at 30-16.
San Francisco improved to 8-2 since the break, and its offense is coming around. The Giants have plated at least six runs five times in their last seven games after reaching the six-run mark five times in their previous 31 contests.
Posey and Cabrera are leading the resurgent offense, with Posey batting .545 with two homers and 15 RBIs in the last eight games and Cabrera hitting .441 with 11 runs scored.
"I'm just trying to have a good approach every time out," Posey said.
Posey was behind the plate to catch Vogelsong, who allowed four hits over seven innings to lower his home ERA to 1.41.
Bumgarner (11-6, 3.12 ERA) has been almost as good at AT&T Park, going 7-1 with a 1.81 ERA in eight starts and compiling a 1.14 ERA in winning his last four there. Against the Padres (41-57) in San Francisco on April 29, the left-hander gave up one run in 7 2-3 innings in a 4-1 victory. The Giants have won his last five starts in the series.
San Francisco is 5-2 against the Padres this year, and has won nine of 11 meetings at AT&T Park.
Chase Headley, who leads San Diego with 11 homers and 50 RBIs, is 4 for 29 with a double and three RBIs in eight games in San Francisco since the start of last season. His double came off Bumgarner in the Giants' 6-5 win at Petco Park on June 6, Headley's lone hit in six at-bats against him this season.
The Padres give the ball to Edinson Volquez (6-7, 3.34), who threw a one-hitter for his first complete game in Thursday's 1-0 win over Houston. The righty struck out five and walked three, and the lone hit was an infield single in the fourth inning that bounced off his glove.
"To do it in the major leagues, complete game, one-hit shutout, that was good," said the righty who leads the majors with 70 walks.
Volquez is 3-0 with a 1.34 ERA in his last five starts, with the Padres winning each after going 1-5 with a 5.72 ERA in his previous seven. He has been hit-or-miss in his four lifetime starts against the Giants, however, posting a 2.08 ERA in two of the games but a 16.50 ERA in the other two.
Bumgarner's last start came in Atlanta on Thursday, and he gave up only three hits over seven innings, but two of them were solo homers. He ended up permitting three runs while striking out eight in a 3-2 loss.
Updated July 24, 2012