"It was a great effort by Wandy," Astros manager Cecil Cooper said. "He had everything working tonight. He made some huge pitches, I thought, to get Manny and struck him out twice."
The win pushed the Astros over the .500 mark (45-44) for the first time this season and to within three games of the first-place St. Louis Cardinals in the National League Central. They've won seven of nine games since getting shut out in consecutive games in San Francisco on July 3-4.
Tim Byrdak, Alberto Arias, LaTroy Hawkins and Jose Valverde polished off the Astros' second consecutive shutout by combining to throw the final three innings. Arias extended his scoreless streak to 20 1/3 innings, and Valverde nailed down his ninth save.
"These guys [the Dodgers] have been playing good baseball and have been in first place the whole year, and what the Astros are doing will make everyone think," Valverde said. "We're not too far out of first place, too. If we can win two or three games here, it would be nice."
Rodriguez (9-6), who shut out the Pirates on five hits in his previous start July 8, allowed five hits and two walks and struck out six batters. He has not allowed a run in 17 consecutive innings over three starts, during which he has a 0.41 ERA.
"He's been great," said Astros first baseman Lance Berkman, who left the game in the eighth inning with a mild left calf strain. "We've needed him to do that. We have to have somebody besides Roy [Oswalt] that can have a shutdown-type game. Not that the other guys can't, but Wandy's been doing it pretty consistently now. They're a good 1-2 punch."
Dodgers starter Randy Wolf -- the former Astro -- retired 14 of the first 16 batters he faced before giving up a home run to perhaps the most unlikely power source in the starting lineup: backup catcher Humberto Quintero, who rocketed a first-pitch fastball over the right-center-field wall to give the Astros a 1-0 lead in the fifth. It was his first homer since Aug. 28, 2008, breaking a team-long 128-at-bat drought.
"I played with Wolf last year and caught him a lot, and the first at-bat he threw everything away," Quintero said. "The second at-bat I was looking for the same pitch away, and he threw it and I hit it hard. I didn't know it was gone because I hit a line drive."
Rodriguez got a terrific sliding catch by Hunter Pence in right field to retire Ramirez in the first inning, and Rodriguez struck him out swinging in the fourth and sixth innings.
"Rodriguez pitched a real good game against us in Houston also," said Dodgers manager Joe Torre, whose team was held to five hits and one run in six innings by Rodriguez on April 23 in Houston. "We had a couple of opportunities and we just couldn't make anything out of it."
Rodriguez got in major trouble in the fifth, loading the bases with one out for right fielder Andre Ethier. With Ramirez waiting on deck, Ethier hit a grounder to shortstop Miguel Tejada, who stepped on second base and threw to first to complete a crucial double play.
"I used a lot more breaking balls because I saw a couple of hitters couldn't hit my breaking ball," Rodriguez said. "My location was very good today, too."
The Astros chased Wolf from the game in the seventh on consecutive singles by Carlos Lee, Tejada and Pence that loaded the bases with no outs. Kaz Matsui greeted reliever Guillermo Mota with an RBI single, and Tejada scored on Quintero's double play to make it 3-0. Quintero didn't get credit for an RBI, but his homer in the fifth proved to be the game-winner.
"He's swung the bat well, and he has swung it pretty good once he's come back from that head injury or that little concussion that he had back a month and a half or so ago," Cooper said. "He has started to play more and started to swing the bat better."