ST. LOUIS -- The Houston Astros didn't pitch particularly well on Monday, and their defense has had better days as well. But it didn't really matter, because they didn't score, either, making it impossible to beat the St. Louis Cardinals in the opener at Busch Stadium.

The Cardinals rolled to a 7-0 win before 40,061 fans who watched the home team stretch its lead in the National League Central to six games over the Astros and five over the second-place Reds, who were idle on Monday.

In the Wild Card race, the Astros are still in sixth place, 4 1/2 games behind the first-place Padres.

The Astros haven't scored since Saturday. They were shut out by Dave Bush in Milwaukee on Sunday, and Cy Young Award candidate Chris Carpenter sailed through his 24th career complete game and his 12th shutout on Monday. He yielded six hits, all singles.

Even a perfect output from the defense couldn't have saved this game, and when Carpenter is handed any kind of significant lead, the night is pretty much over.

"We gave them some runs, and we didn't score any," manager Phil Garner said. "Obviously, we can't give Carpenter any runs. He's pitching extremely well, and he did again tonight."

Taylor Buchholz -- who was called up on Sunday night and told that he had a good chance to pitch this game in place of Andy Pettitte -- allowed five runs, only two of which were earned. His undoing began in the fourth, when Adam Everett made his second error of the game, bobbling an Aaron Miles ground ball for a split-second, allowing the speedy shortstop to beat the throw by a hair.

That opened the floodgates. Chris Duncan doubled to right, moving Miles to third, and after Buchholz intentionally walked Albert Pujols, Garner called on Fernando Nieve, who coaxed a ground ball from Scott Rolen. But the groundout to first scored Miles, and after Nieve intentionally walked Scott Spiezio, he also walked Juan Encarnacion, forcing in a run. Ronnie Belliard capped the five-run inning with a three-run triple.

Everett, who was also charged with a tough error in the second on a grounder by Carpenter, hadn't erred twice in a game since May 1, 2005.

"Tonight we needed to pick up our shortstop -- he's picked us up a ton of times," Garner said. "We just didn't play a good ballgame. Carpenter had something to do with that. He's pitching very, very well."

"I just never got a handle on it, really," Everett said of the fourth-inning error. "Obviously, it cost us five runs. When you've got a guy like Carpenter on the mound, you know [that down] two runs, you've got a chance. But [five] runs in the fourth inning, it's tough to overcome that."

The Cardinals' two-run third inning bothered Buchholz as much as the fourth. He yielded a leadoff walk to Chris Duncan and a base hit to Pujols, recorded two quick outs, then gave up RBI singles to Encarnacion and Belliard.

"The couple of leadoff walks, here and there -- you can't be doing that," Buchholz said. "That one inning when they scored two runs, that's three ground balls right there, just in the wrong spots. The one on Encarnacion, I was trying to go up, and I missed right down the middle to him."

"He just didn't locate his pitches," Garner said. "We walked a couple of guys, but we had a couple of strikes on guys early in the count and didn't put them away. He just didn't make his pitches."

Carpenter, on the other hand, had few troubles with the Astros lineup, which has not scored since Lance Berkman hit a 500-foot moonshot off the scoreboard in the seventh inning of Saturday's game at Miller Park.

This time, though, the Astros were dominated by a pitcher who has had a similar effect on plenty of teams in the league.

"He can throw anything for a strike," Everett said of Carpenter. "And he can throw it to both sides of the plate. When you can do that, throwing 94, 95 [mph], taking some off of his cutter, anywhere from 85 to 90 [mph], and he's got that big curveball. It's why he won the Cy Young last year and may win it again this year."

Garner did not feel that Carpenter's dominance was a result of a lack of energy on the Astros' part.

"In our game, when you have good pitching, it shuts down offense," Garner said. "You can't do anything. You can't have any fire. We can stand out there and butt heads on the dugout all day long and forearm shivers and scream and hooplah and hollar and go to the plate, and if the guy throws where he wants to throw the ball, you're still not going to do anything. That's what happened tonight. Tonight was a well-pitched ballgame against us. We got down, and he was able to cruise."