Giants 3, Padres 1: Pablo Sandoval drove in two runs and Ryan Vogelsong tossed six strong innings as visiting San Francisco won the opener of the three-game series.

Vogelsong (14-9) gave up one run on five hits and Santiago Casilla retired pinch-hitter Carlos Quentin with two runners on in the ninth for his 25th save, giving the Giants their 15th win in their last 22 games at Petco Park.

After Hunter Pence drove in a run in the second, San Francisco extended its lead in the third on Sandoval’s two-run double off Andrew Werner (2-3), who struggled in his second straight start against the Giants.

Werner gave up three runs over 4 2/3 innings and has allowed eight runs in 8 1/3 innings against the Giants in his last two outings. The Padres fell to 5-11 against San Francisco this season and have lost seven of their last 10 games overall.

Giants catcher Buster Posey went 2-for-4 to raise his batting average to a National-league leading .334, and he’s batting .381 (16-for-42) with three homers and 11 RBIs in his last 10 games at Petco Park.

GAME NOTEBOOK: Giants 2B Marco Scutaro singled to extend his hitting streak to a career-best 16 games before exiting in the sixth inning because of illness. … The Padres are looking for their first series victory over the Giants since taking two of three in the final series of the 2010 season. …San Francisco LF Xavier Nady belted his first triple since 2008.