Matt Kemp singled before Gibbons connected against Fernando Abad (0-1), hitting a drive over the wall in right-center for his fourth homer. Gibbons also had a pinch-hit RBI single in the sixth that gave Los Angeles a 2-1 lead.
Bourn singled in a run in the seventh, tying it at 2, but was caught in a rundown to end the inning. Wallace set up the run with a one-out double off Ronald Belisario that rolled up the hill in center field before bouncing off the wall.
Kemp tripled and scored when Gibbons delivered in the sixth. Kemp briefly considered breaking for home after a bad throw to third on his hit, but the Astros chased the ball down quickly and he returned to the bag.
Hiroki Kuroda pitched six innings for the Dodgers, yielding just one run and four hits. He struck out three and walked two.
Bourn's two-out single tied it at 1 in the fifth. After Keppinger walked, Pence grounded out to leave the bases loaded.
That rally came after the Dodgers grabbed the lead in the top half of the inning against J.A. Happ. Rod Barajas reached on a leadoff single and advanced on Kuroda's sacrifice. Jamey Carroll singled him in with two out.
Happ allowed seven hits in five innings.
NOTES: Houston RHP Henry Villar made his major league debut in the 11th inning. He committed an error before striking out Carroll. ... The Astros are waiting to see what the next step will be for RHP Felipe Paulino, who is on the 60-day disabled list with a right rotator cuff injury. He threw a simulated game Thursday and said Friday he hopes he'll be able to pitch again before the season is over. ... Dodgers C Brad Ausmus will start on Sunday against the Astros. Los Angeles manager Joe Torre said he thought it would be nice for 41-year-old Ausmus to play against the team where he spent the majority of his career.