Madison Bumgarner pitched a five-hitter with 12 strikeouts, Brandon Belt broke up a pitcher's duel with two solo homers, and the San Francisco Giants beat the Houston Astros 3-1 on Tuesday night. It was his third career multihomer game and second this year for the defending champion Giants, who bounced back at home after being swept by the Cubs in four games over the weekend at Wrigley Field. Bumgarner (13-6) outpitched fellow southpaw Scott Kazmir (6-7) in an anticipated interleague matchup of top lefties for the World Series MVP's eighth career complete game and second this season.