SAN FRANCISCO -- Hunter Pence broke a sixth-inning tie with a bases-loaded, two-run double Saturday afternoon as the San Francisco Giants did all their scoring in the inning en route to a 3-2 interleague victory over the Baltimore Orioles.
Chris Davis rocketed his 42nd home run, a solo shot, in the eighth inning for the Orioles, who led 1-0 before the Giants came to the plate in the sixth.
Left-hander Wei-Yin Chen (6-5) shut out the Giants on one hit through five innings before Andres Torres sparked the game-changing sixth with a leadoff single.
After a sacrifice bunt by Gregor Blanco, Marco Scutaro tied the game with an RBI single that scored Torres from second.
Joaquin Arias flied out for the second out, and the Giants then appeared to catch a bad break when Brandon Belt's blast to center field bounced over the fence for a ground-rule double, forcing Scutaro to stop at third.
Chen then intentionally walked Buster Posey after falling behind 2-0, and Pence followed with the Giants' first extra-base hit with the bases loaded in almost a month, a shot into the right-field corner that scored Scutaro and Belt for a 3-1 lead.
The clutch hit following an intentional walk was the second in the first two games of the series. Major-league RBI leader Davis broke a 10th-inning tie with a two-run double after an intentional walk in Baltimore's 5-2 win Friday night.
Guillermo Moscoso (1-0), who relieved Giants starter Chad Gaudin in the sixth inning, got the win after throwing two shutout inning. Santiago Casilla pitched the eighth, allowing Davis' home run, before Sergio Romo recorded his 28th save after giving up a leadoff single to pinch-hitter Henry Urrutia in the ninth.
Romo got Davis to ground out to second base to end the game with Urrutia, the potential tying run, on first base.
Davis' home run, a monster shot that landed 10 rows deep in the center-field bleachers, was his sixth in 13 interleague games this season.
Adam Jones drove in Nate McLouth in the fourth inning with the earlier run for the Orioles, who had won three in a row overall and five straight in interleague play.
Chen lost despite allowing three or fewer runs for the 36th time in 46 major-league starts. He surrendered three runs on five hits, striking out two and walking one.
Despite getting out-hit 8-6, the Giants won for a fourth win in 13 interleague games this season.
Nick Markakis had three of Baltimore's eight hits, all singles.
The Orioles stranded 10 baserunners, including two in the eighth after one-out singles by Markakis and J.J. Hardy. Casilla struck out Ryan Flaherty and pinch-hitter Matt Wieters to retain the Giants' 3-2 lead.
Gaudin got no decision after laboring through five innings, throwing 93 pitches. But he worked his way through two hits and three walks to allow only the third-inning run, which was unearned.
The first-year Giant has now allowed two or fewer runs in nine of his 11 starts.
NOTES: Pence also had the Giants' most recent extra-base hit with the bases loaded, a fifth-inning triple in RHP Tim Lincecum's no-hit game in San Diego on July 13. ... Both hits against Gaudin were by left-handed batters. Righties went 0-for-7 against Gaudin; he has allowed right-handed batters to hit just .168 against him this season, the lowest mark in the National League. ... Markakis' 3-for-4 effort allowed him to improve his career interleague batting average to .343, the highest all-time among players with at least 400 at-bats. Mike Piazza (.340) had moved ahead of Markakis after the right fielder's 0-for-5 outing Friday night. ... The Orioles announced before the game that RHP Scott Feldman, whose turn in the starting rotation was skipped this week because the team had two off days, would make his next start Monday in the series opener at Arizona.