HOUSTON - Chris Carpenter became baseball's first 20-game winner this season, and St. Louis took advantage of Roger Clemens' injury to beat the Astros 4-2 Saturday night.
Clemens came out after five innings because of a strained left hamstring, leaving him without a decision in a marquee matchup of NL Cy Young Award candidates.
Carpenter won his 12th straight decision over 15 starts, pitching his major league-leading seventh complete game.
The right-hander allowed eight hits, including four for extra bases, in his 20th career complete game. It was his fourth victory this season over Houston, which has managed just three runs off him in 33 innings. He struck out eight, walked two and threw 120 pitches.
It also was Carpenter's 10th straight road victory, the first NL pitcher since Bob Gibson won 12 in a row in 1970.
Clemens said he tweaked his hamstring during his at-bat in the second inning. The Astros said he was day-to-day, and Clemens said he hoped to make his next scheduled start Friday.
There was an audible, collective groan heard in the stadium from the sold-out crowd of 42,817 when pinch-hitter Chris Burke was introduced to bat for Clemens in the bottom of the fifth.
Clemens leads the major leagues with a 1.52 ERA, but Houston has been shut out eight times in games Clemens started, including five 1-0 games.
The Astros trailed 2-1 when Clemens left, but Lance Berkman's leadoff homer in the sixth took him off the hook.
Clemens gave up four singles, two of them when Albert Pujols and Yadier Molina dribbled balls down the third-base line on full swings. The Rocket had two strikeouts and two walks.
