Pittsburgh, PA (Sports Network) - Paul Maholm tossed eight strong innings and Jason Bay's RBI triple in the bottom of the fifth provided the difference, as the Pittsburgh Pirates clipped the Houston Astros, 4-3, in the rubber match of a three-game set at PNC Park.

Maholm (4-5) gave up three runs -- two earned -- on eight hits to record his second straight win.

"I started getting quick outs and allowed the defense to stay on their toes and they made some great plays," Maholm said.

Jason Michaels clubbed a three-run homer for the Pirates, who have won three of their last four games. Jack Wilson had two hits and scored a run.

Brandon Backe (4-7) allowed four runs on nine hits in six innings for Houston, which has dropped seven of its last eight games. Backe added an RBI single.

Ty Wigginton and Brad Ausmus both went 2-for-3 and scored a run, while Hunter Pence drove in a run and scored another.

"We just didn't get the big hit when we needed it," Houston manager Cecil Cooper said. "We just seem like we were a step short in the whole series. We got to figure out what we got to do to turn it around."

The Pirates broke a 3-3 tie in the fifth. An infield single by Nate McLouth extended the inning before Bay smacked a deep fly ball that glanced off the glove of center fielder Jose Cruz Jr. for an RBI triple. After Michaels worked a walk, Backe fanned Adam LaRoche to escape further damage.

Maholm retired Houston's 3-4-5 hitters in order in the eighth and Matt Capps nailed down his 13th save of the season with a scoreless ninth.

The Astros took a 1-0 lead in the top of the first. Pence doubled to open the game and, after Kazuo Matsui and Miguel Tejada were retired, Lance Berkman hit a dribbler up the middle. Wilson ranged over to his left and fielded the grounder, but his throw eluded the first baseman. Berkman was credited with an infield hit and the miscue allowed Pence to score. On the play, Berkman advanced to second, where he was stranded after Carlos Lee flied out to end the inning.

Pittsburgh pulled ahead in the next frame on Michaels' home run. After a leadoff single by Wilson and a two-out walk to Bay, Michaels drove Backe's 2-0 fastball into the seats in right-center to put the Pirates on top, 3-1.

Houston quickly evened the score in the top of the second. Wigginton, Ausmus and Backe each singled to bring in a run and Pence followed with a sacrifice fly.