Matt Cain looks to pick up a rare victory against the lowly Padres -- and win a career-high sixth straight start -- in Thursday's finale at Petco Park.After dropping Tuesday's series opener 6-5 on Logan Forsythe's game-ending homer, the Giants (32-25) bounced back with a 6-5 victory Wednesday. Gregor Blanco homered and scored twice, and is 5 for 10 with a triple, double and four runs in the series.San Francisco has won eight of 10 overall and each of Cain's last six starts.Cain (6-2, 2.62 ERA) has earned the win in his last five, pushing his career record to 75-75, his first time at .500 since he was 17-17 in 2007."It kind of stinks to have to think, 'to get back to .500,' but that's the way it goes," Cain said after allowing a run and five hits while striking out seven in eight innings of Saturday's 2-1 victory over the Chicago Cubs.The two-time All-Star, who hasn't won six consecutive starts since May 17-June 14, 2009, has a major league-worst 3.87 run support average since his 2005 rookie season, an obvious contributor to his record.His teammates have had an especially difficult time giving him much help at Petco.Cain has a 2.81 ERA in 13 career starts at San Diego's spacious ballpark, but has been backed with one or no runs eight times -- the reason he's 2-6. He has made six overall starts against the Padres since his last victory Sept. 9, 2010, and has a 2.39 ERA in the last four.He'll be facing a San Diego offense that ranks as one of the worst in the majors with 3.28 runs per game and a .225 batting average. The Padres (19-38), losers in 12 of 15, were 1 for 11 with runners in scoring position Wednesday and are far and away baseball's worst team in such situations (.189)."We had a couple of chances but couldn't get the big hit," manager Bud Black said.Carlos Quentin has typically come through in his seven games since being removed from the disabled list. He is hitting .481 with five homers, four doubles, nine RBIs and has scored nine times, but is batting .133 with a homer and double in 15 career at-bats against Cain.Although San Francisco's offense hasn't helped Cain's cause in San Diego, it could be poised for a big game as Jason Marquis makes his Padres debut after signing a minor league deal last week.Marquis, who will be pitching for his sixth team in the last five seasons, was released by Minnesota on May 26 after going 2-4 with an 8.47 ERA in seven starts -- including a 15.19 ERA in losing his final three outings. The right-hander gave up a run and five hits in seven innings for Double-A San Antonio last Thursday.Marquis, who has a 2.93 ERA in six career starts at Petco, made two starts against San Francisco last season with very different results. He threw a five-hitter in a 3-0 win for Washington on April 29, but was tagged for eight runs and 10 hits in four innings of an 8-1 loss for Arizona on Aug. 3.