HOUSTON (AP) – Roger Clemens got his 345th win, allowing one run in six innings to lead Houston over the Pittsburgh Pirates 5-2 Thursday night and complete a three-game sweep for the Astros.

Clemens (4-4) struck out five and allowed four hits, yielding two runs or fewer for the eighth time in 10 starts. His 2.32 ERA since June 22 leads NL starters.

Morgan Ensberg hit a three-run homer for the Astros, who have won seven of nine and earned their first series sweep since they took three in a row from the Chicago Cubs at Wrigley Field in mid-June.

Freddy Sanchez hit a sacrifice fly and Ronny Paulino had an RBI groundout in the ninth off Brad Lidge. Pittsburgh mustered just four runs in the series and eight in six games at Houston this season.

Ensberg’s 20th homer of the season was his first since he came off the disabled list on Aug. 1 after recovering from a bruised right shoulder. Before Ensberg’s home run, the Astros struggled against starter Tom Gorzelanny (2-3).

The 24-year-old left-hander was almost as good as Clemens, allowing five hits with six strikeouts. He also walked five and gave up two RBI singles to Brad Ausmus.

Gorzelanny walked Ensberg and Luke Scott in the second, and Ausmus singled sharply single to center for his first RBI since he hit his third career grand slam in Arizona on Aug. 5.

In the fourth, Scott beat out a grounder that second baseman Jose Castillo fielded before throwing over the head of first baseman Xavier Nady. With one out, Ausmus singled to center again, securing his sixth multi-RBI game of the season.

Clemens retired nine consecutive batters before Nate McLouth’s one-out single in the sixth. Jack Wilson followed with a line-drive double to left, but McLouth only reached third.

Sanchez, the NL’s batting leader, then sent a fly to right to score McLouth.

Clemens was finished done after Jeromy Burnitz walked and Nady singled starting the seventh. He was replaced by Chad Qualls, who gave up a tying three-run homer after relieving Clemens in a 7-6 loss to Arizona on July 30. Qualls did the job this time.

After Castillo bunted into a fielder’s choice, Paulino beat out a slow bouncer to load the bases. Joe Randa pinch-hit for Gorzelanny and grounded to Ensberg, who stepped on third and threw to Berkman, the Astros’ 122nd double play of the season.

Salomon Torres replaced Gorzelanny, and Craig Biggio doubled down the left-field line to start the final rally. Torres intentionally walked Lance Berkman, and John Grabow truck out Aubrey Huff.

Pittsburgh manager Jim Tracy then yanked Grabow for rookie Matt Capps, who’d given up three home runs in his last eight outings. Ensberg whiffed on Capps’ first pitch, then hit the second one into the left-field seats.

Houston’s bullpen, with an NL-leading 2.83 ERA since the All-Star break, scattered five hits the rest of the way, stretching its scoreless streak to 10 2-3 innings.

Notes: Willy Taveras singled to extend his hitting streak to 13, a career high. … Clemens made his 681st career start, tying Pud Galvin for ninth. … The Astros failed to score in the first inning for the first time in six home games against Pittsburgh this season.