HOUSTON -- The Milwaukee Brewers have a winning formula working early in the season.
J.J. Hardy drove in two runs for Milwaukee and Prince Fielder had an RBI and two runs scored. Bush (3-0) allowed two runs and seven hits for the NL Central leaders, who have won 13 of 15 to turn around a 4-9 start.
"We don't talk about it," said Bush, who threw 84 pitches. "We know we have a solid team. We knew that at the beginning of the year, when we weren't playing very well."
The Brewers' bullpen came in with a 3.67 ERA, second-best in the NL.
"There's no hesitation at all to give it up and let those guys finish it out," Bush said.
Ortiz (2-2) gave up two runs in the sixth after replacing Mike Hampton, who left after four innings with a cut on his left thumb.
Hampton said he hurt the finger on a soap dispenser in a shower during the team's trip to Chicago last weekend. He said the injury affected his grip in Tuesday's start.
"I kind of glued the wound shut," Hampton said. "And then it opened up after the first [inning], and it just never got any better. I didn't have a whole lot of feel for any of my pitches."
Matsui became the latest player to swipe home in the first inning, five days after Bourn did it in Colorado on the front end of a double steal.
The Houston second baseman led off with a double and advanced to third on Bourn's bunt single. With slugger Lance Berkman at the plate, Bush made a pickoff throw to first that caught Bourn leaning toward second, putting him in a rundown.
Matsui dashed to the plate and scored without a throw as the speedy Bourn scampered between first and second. After a couple of throws by the Brewers, Bourn dove safely back to first.
"It's something that just happened to happen," Bourn said. "When I saw him break for home, I did what I could to stay alive after that."
Fielder tied it with an RBI double in the fourth after Ryan Braun led off with a walk against Hampton.
Braun rounded third on Fielder's drive to the left-field corner, despite a stop sign from third-base coach Brad Fischer. Shortstop Miguel Tejada took the relay, then hesitated as Braun pulled up a few strides from home. But Braun decided to break for the plate and Tejada's late throw was off target.
Hardy's RBI single scored Fielder to give Milwaukee a 2-1 lead.
Hampton departed after throwing a season-low 60 pitches. Ortiz retired the side, then led off the Astros fifth with a tying homer to left, the seventh of his career.
Braun and Fielder walked leading off the sixth and Braun scored on Hardy's bloop single to right. Fielder trotted home on Casey McGehee's sacrifice fly for a 4-2 lead.
Macha called the offensive output "workmanlike," and the Brewers were certainly efficient -- five hitters walked and three of them scored.
Astros reliever Jeff Fulchino shut out the Brewers over the final three innings.
Coffey has not allowed a run in 14 of 18 appearances this season. ... Ortiz last homered on July 29, 2003, against Houston's Roy Oswalt. It was the first home run by a Houston pitcher since Aug. 1, 2008, when Brandon Backe hit one off the New York Mets' Pedro Martinez. ... The Brewers placed second baseman Rickie Weeks, out for the rest of the season with a wrist injury, on the 15-day disabled list and recalled second baseman Hernan Iribarren from the minors. RF Corey Hart took the top spot in the batting order, but Macha hasn't settled on a leadoff man for the long term. "We have to try to figure that out," he said.