Hunter Pence's two-run double in the sixth inning proved to be the difference as the San Francisco Giants held off the Baltimore Orioles, 3-2, in the second test of a three-game series.
Marco Scutaro had an RBI and a run scored for the Giants, who bounced back from a 5-2, 10-inning loss in Friday's series opener.
San Francisco starter Chad Gaudin allowed one unearned run on two hits while striking out six over five innings. Guillermo Moscoso (1-0) tossed two scoreless innings of relief to pick up the win.
"It started with Chad," Giants manager Bruce Bochy said. "He logged some pitches there, but he competed so well out there to keep them to one run. Guillermo [Moscoso] had two solid innings. We needed it. He came through for us."
Chris Davis hit his MLB-leading 42nd homer of the season for the Orioles, who had a three-game winning streak snapped. Adam Jones drove in a run.
"I know their record doesn't say it, but they're a good team," Davis said. "Any time you come in here, you're going to have a battle on your hands. That's the reason they've won the World Series the last few years. They know how to win."
Wei-Yin Chen (6-5) started for Baltimore and gave up three runs on five hits over six innings.
Baltimore, which left the bases loaded in the second, scored once in the third. Nate McLouth led off with a walk and advanced to third two batters later when Chris Davis made it to second on first baseman Brandon Belt's throwing error. McLouth scored on Jones' sacrifice fly to center.
Meanwhile, Chen was dominant on the mound. He retired 13 straight batters before running into trouble in the sixth. Andres Torres led off with a single, moved to second on a sacrifice bunt and raced home on Scutaro's single to left-center field. Belt hit a ground-rule double to right-center field and Buster Posey was intentionally walked to load the bases. Pence followed with a two-run double to right, making it 3-1 San Francisco.
Davis' homer off Santiago Casilla in the eighth cut the gap to one.
Sergio Romo pitched a scoreless ninth to record his 28th save of the season.
Nick Markakis went 3-for-4 for the Orioles ... Baltimore went 0-for-8 with runners in scoring position and stranded 10 ... Matt Cain pitches the series finale Sunday for San Francisco against Bud Norris.