PITTSBURGH (AP) -- It looked as if it would be a short night for Paul Maholm, after the Pittsburgh starter allowed three runs in the first two innings against Houston.
But Pirates manager John Russell was confident the left-hander would settle down, and Maholm delivered in a big way.
He wound up going eight strong innings, Jason Michaels hit a three-run homer and the Pirates beat the Astros 4-3 Thursday night.
"That's the way [Paul] is," Russell said. "He has that one inning. Then he settled in and did really well. He did a great job from the third inning on."
Starting with a sacrifice fly from Hunter Pence in the second inning, which tied the game at 3, Maholm retired 20 of the final 23 batters he faced. Maholm (4-5) allowed two earned runs and eight hits, struck out one and did not walk a batter to win his second consecutive start.
"After the second inning, I settled in and let them hit ground balls," Maholm said. "I tried to go as long as I could. It's my goal to be effective and get deep into the game."
Matt Capps allowed a pair of runners in the ninth inning, but got Pence to fly out to deep center for his 13th save.
"The ball Pence hit stayed up just long enough," Capps said. "It worked out."
Jason Bay added a run-scoring triple to break a 3-3 tie in the fifth, helping Pittsburgh beat Houston for the second consecutive night. The game was played in a crisp 2 hours, 24 minutes.
The Astros have lost seven of eight, even though they scored more than two runs for the first time during the stretch, and dropped one game above .500 for the first time since May 8.
"We didn't swing it very well tonight," Astros manager Cecil Cooper said. "We didn't hit any balls sharp. We didn't have very good swings tonight. Tomorrow, we have to go back to the drawing board and find a way to get things going because we're not hitting at all. Seven, eight games, you figure someone will break out and we haven't been able to do that."
The Pirates' go-ahead rally in the fifth came with two out against Brandon Backe. Nate McLouth reached on an infield single before Bay hit a deep drive to center that was just out of the reach of Jose Cruz Jr., who crashed into the wall. McLouth scored and Bay had his second triple of the season.
Backe (4-7) lasted six innings, allowing all four runs on nine hits, striking out two and walking two. The right-hander, who had won four consecutive starts against Pittsburgh, lost to the Pirates for the first time since Sept. 11, 2004.
"It stinks," Backe said. "It seems like the other team is getting a lot of cheap hits. That's just the game and the way it's played. It's just something we have got to get out of."
Michaels continued his tear at the plate, homering in consecutive at-bats spanning three days by driving a fastball from Backe 384 feet in the first to give the Pirates a 3-1 lead.
The backup outfielder had a pinch-hit grand slam in Pittsburgh's 5-4 win over St. Louis on Monday, then didn't play again until Thursday. He's 6-for-13 with two home runs and 11 RBIs in his past six games.
"It my role to give the guys days off," Michaels said. "I got a 2-0 fastball, and got it on the sweet part of the bat."
The Astros scored in the first when Pence came home on a single by Lance Berkman and a throwing error by Pirates shortstop Jack Wilson. They added two more in the second when Backe drove in Ty Wigginton and Pence's sacrifice fly scored Brad Ausmus.
After the game, Pittsburgh activated C Ryan Doumit from the disabled list and optioned C Ronny Paulino to Triple-A Indianapolis. Doumit, who was out with a fractured left thumb, had been on a rehab assignment with Double-A Altoona. ... Houston optioned C J.R. Towles to Triple-A Round Rock and purchased the contract of C Humberto Quintero from its top affiliate. ... The Pirates completed a stretch of 22 consecutive games against teams from the Central Division. They went 11-11. ... Berkman went 1-for-4, but still is hitting .419 (26-for-62) against left-handed pitching this season.