Manny Ramirez singled with one out in the eighth off Santiago Casilla (1-2), and after he was forced out at second on Ronnie Belliard's grounder, Blake lined a shot over the left field wall to lift the Dodgers to the victory.
Ramirez went 3-for-3 with an RBI and Rafael Furcal collected a pair of hits and scored a run for Los Angeles.
Jeff Weaver (5-1) was credited with the win for pitching a scoreless seventh and Hong-Chih Kuo collected his second save despite allowing a walk and a base hit in the ninth. Dodgers starter Chad Billingsley held the Giants to two runs over six innings.
San Francisco starter Barry Zito went six innings, yielding a pair of runs on six hits while striking out six.