SAN FRANCISCO — Pablo Sandoval hit a three-run homer and a solo shot, and the NL West-leading San Francisco Giants reduced their magic number to clinch the division to four by beating the Colorado Rockies 9-2 on Thursday.

Buster Posey also connected for the Giants to back another strong start by Barry Zito (13-8) as San Francisco completed a four-game sweep.

Zito won his fifth straight decision and has done everything to earn himself a spot in the postseason rotation after being left off all three rounds for the 2010 World Series champions.

The second-place Dodgers were set for a night game at Washington, trailing by 9 1/2 games. San Francisco (87-63) moved a season-best 24 games above .500, its best since finishing the 2003 season 39 games over.