Giants 8, Dodgers 4: Joaquin Arias homered and drove in a career-high five runs and Matt Cain tossed seven strong innings as visiting San Francisco completed its first three-game sweep at Dodger Stadium since 2007.

Cain (13-5) gave up one run on seven hits with no walks for the Giants, who moved 2 1/2 games ahead of the Dodgers in the National League West.

San Francisco scored three runs in the first on Pablo Sandoval’s sacrifice fly and Arias’ two-run shot off Chris Capuano (11-9), who was pulled with no outs in the sixth after Sandoval’s RBI single.

Shawn Tolleson replaced Capuano and promptly gave up Arias’ run-scoring double before walking Justin Christian with the bases loaded. Christian later provided the defensive play of the game with his diving catch on Juan Rivera's liner to deep left field in the seventh.

Arias continued his impressive night with a two-run double in the seventh, and the Dodgers scored three runs in the eighth before Santiago Casilla induced A.J. Ellis to ground into an inning-ending double play.

The Giants never trailed in the series, and starting pitchers Madison Bumgarner, Tim Lincecum and Cain allowed just two earned runs with 19 strikeouts and one walk.

Matt Kemp went 1-for-5 and is 2-for-25 in his last seven games for Los Angeles, which hit five doubles but fell to 6-12 at home since the All-Star break.

GAME NOTEBOOK: Giants C Buster Posey was scratched from the starting lineup with a tight hamstring. …San Francisco improved to 48-16 when scoring first. … Dodgers RHP Rubby De La Rosa gave up two runs in his first appearance since having Tommy John surgery last year. … Since 2010, Cain is 32-1 in the 46 games he has received at least three runs of support. … The two rivals will meet six more times, including a season-ending three-game set at Chavez Ravine.