Giants 3, Astros 2: Pinch hitters Joaquin Arias and Hector Sanchez delivered run-scoring hits in the ninth inning as National League West-leading San Francisco rallied for its season high-tying fourth straight road victory.
After Houston took a 2-1 lead in the eighth on a wild pitch by Matt Cain, the Giants took advantage of Houston's weak bullpen to get their six-game road trip off to a good start. Brandon Belt led off the ninth with a single off Wesley Wright and scored when Arias ripped a double down the third-base line off Wilton Lopez (5-3).
Lopez struck out Brandon Crawford, but Sanchez followed with a single that plated Arias for a 3-2 advantage. San Francisco had been 0-for-11 with runners in scoring position prior to Sanchez's hit.
Santiago Casilla (5-5) recorded the final two outs of the eighth and Sergio Romo worked a perfect ninth for his seventh save.
The game was scoreless until Angel Pagan deposited a 1-1 offering from Bud Norris into the seats in right field with two outs and none on in the top of the fifth. Houston answered quickly as Fernando Martinez led off the bottom of the inning with an upper-deck shot off Cain.
Brett Wallace collected three of the six hits by the Astros, who have lost 10 of 12 overall and 16 of 19 at home.
GAME NOTEBOOK: San Francisco 3B Pablo Sandoval and SS Crawford teamed up to record the final out of the first inning. Sandoval chased down Castro's foul pop and made a diving attempt to catch it. As he fell, Sandoval knocked the ball back into the air and Crawford made a diving catch to end the frame. ... Astros OF Justin Maxwell, who has not started since Aug. 21 due to a bruised right index finger, will attempt to swing a bat Wednesday. ... RHP Guillermo Mota returned to the Giants after serving the 100-game suspension he received for testing positive for Clenbuterol. LHP Jeremy Affeldt was placed on paternity leave to clear a spot on the roster for Mota.