HOUSTON -- Had it not been for an injury to starting pitcher Felipe Paulino, the most disappointing development to emerge from Minute Maid Park for the Astros on Sunday was pitcher Russ Ortiz not getting credit for a win for his terrific work in relief.

The contributions of Ortiz topped a long list of key performances for the Astros, who scored three times in their final two-bats to pull away from the Pittsburgh Pirates and cap the series with a 6-4 win. Houston has won three consecutive series and seven of its past 10 games.

Ortiz threw 4 1/3 scoreless innings of relief after Paulino left in the second with a strained right groin. It was the club's longest scoreless relief appearance since Matt Albers went five innings on July 27, 2006, and the longest outing by an Astros reliever since Dave Borkowski went 4 1/3 innings on Aug. 22, 2006.

"That's my job right there, just hold the game where it's at," Ortiz said. "I've been feeling great the last four outings. Everything seems to be clicking. I've been able to get in a fair amount for a long-relief guy, so that helps to keep consistent. You can only be so good throwing bullpens. You have to face hitters."

The solid bullpen work continued with Jeff Fulchino (1-1), who limited the damage in the seventh to two runs when he entered with the bases loaded and no outs to get his first Major League win. Chris Sampson threw a perfect eighth to extend his scoreless streak against the Pirates to 24 innings, and LaTroy Hawkins worked the ninth for his eighth save.

Houston broke a 3-3 tie in the seventh when Matt Kata raced home from second base on Miguel Tejada's two-out infield single. Kata never hesitated when Pirates shortstop Ramon Vazquez made a diving stop and unsuccessfully tried to flip the ball to second baseman Freddy Sanchez to force out Michael Bourn.

"I just tried to get as big of a lead as those middle [infield] guys let me -- a good secondary lead," Kata said. "Once I saw that ball was in play, I'm going at it hard and picking up [third-base coach Dave Clark], and once he keeps waving me just keep going. I'm not turning to look if it gets through. I scored and had to ask someone what happened."

The Astros scored two more in the eighth to take a 6-3 lead on an RBI single by Humberto Quintero, who went 3-for-4 to raise his average to .325, and a pinch-hit double by Jason Michaels to score Lance Berkman.

"It was a great effort by everybody and a team effort," Houston manager Cecil Cooper said. "We used almost the entire roster, everybody that was available today. They all did a great job, particularly our bullpen."

Especially Ortiz, who had to scurry to get prepared to work when Paulino was injured. Paulino allowed three hits and one run in 1 2/3 innings and struck out four of the eight batters he faced. He left the game after throwing his first pitch to Pirates starter Ian Snell in the second.

"I thought he had electric stuff today," Cooper said of Paulino.

Ortiz, who was in the rotation to begin the season, threw 63 pitches, allowing four singles and one walk while striking out four batters.

"I've learned I need to make sure I'm as ready as I can so when I go out there [to the bullpen] for the first couple of innings I'm loose, and as the game goes on I just try to stay loose," he said. "It's one of those occasions -- it was a lot earlier than you'd like to pitch because that means something either happened to the starter or it's not going well."

The Astros rallied after two outs in the second to tie the game on an RBI single by Jeff Keppinger (2-for-4). Back-to-back doubles by Keppinger and Quintero put Houston ahead, 2-1, and Carlos Lee scored Hunter Pence from second on an RBI single in the sixth to make it 3-1.

"Tejada talked to me before the last at-bat and told me to try to hit the ball to first base hard," Quintero said. "That's what I tried to do, and I got the big hit."

Pittsburgh scored twice in the seventh off Tim Byrdak, who allowed all three batters he faced to reach, to tie the game at 3. The damage would have been worse had Fulchino not gotten Adam LaRoche to hit into a double play with the bases loaded to end the inning.

"The main thing is I didn't want to give up the lead," said Fulchino, who was pitching in his 29th career game. "Any time you come in with guys on base you don't want to give up the runs. I was able to limit the damage. I feel bad I couldn't hold it at 3-1, but it worked out in the end."