Chris Carpenter turned in a game eight innings on Thursday night, notching his fifth complete game of the season, but was undone by Lance Berkman's two-out, two-run, game-winning home run in the eighth inning. St. Louis fell to Houston, 6-5, as the Cards' magic number remained at five with 10 days left in the season.

Carpenter may have also seen his Cy Young Award hopes take a blow, as he missed out on a chance at a 16th win and watched his ERA climb. Through 103 pitches, the National League's reigning Cy Young holder was on track for the victory. On a 3-2 pitch, however, Berkman turned a 5-4 Cardinals lead into a 6-5 deficit. It was the slugger's second homer and third extra-base hit of the night.

"I'm trying not to give him a chance to beat me," said Carpenter. "Unfortunately, I spun a cutter in there and he hit it out.

"That's why he puts up the numbers he does. He doesn't miss many mistakes."

The Astros are clinging desperately to the fringes of contention in both the National League Central division and the NL Wild Card race, while the Cards' march to October has taken on an inevitable quality. Even if Houston sweeps this weekend's four-game series, the odds are against the Astros' season lasting beyond Oct 1.

But when Berkman's shot screamed out to right-center field and 32,975 fans went nuts, you wouldn't have known it. The shot was the capper on a typically bizarre, twisting, turning game between the two teams that have dominated the Central for most of its existence.

Carpenter twice watched three-run leads turn into one-run margins. Through seven innings, though, he never let the advantage get away. Morgan Ensberg led off the eighth with a single, and after a sacrifice bunt and a strikeout, Berkman worked a seven-pitch at-bat before pummeling a full-count offering from Carpenter for his second home run of the night.

With a base open, the Cardinals had no desire to give Berkman a hittable pitch. They shied away from simply putting up four fingers, however.

"I'm not sure putting him on to face a guy who's hitting .380 (rookie Luke Scott) is a smart move," said manager Tony La Russa.

Said Berkman: "I was a little surprised, but I wasn't shocked. It was one of those situations where I felt like [I] certainly [might] get walked. At the same time, they might try the old unintentional-intentional where they try to make some tough pitches. Really, I think that's kind of the way it started out."

The one-run lead was enough for Dan Wheeler, who capped four hitless innings of Houston relief by pitching the ninth inning for his seventh save. Dave Borkowski breezed through three perfect frames before handing the game over to Wheeler.

St. Louis built leads of 3-0 and 5-2 with the help of a series of defensive gaffes by the Astros. Two errors, a missed double-play chance, a balk and a wild pitch all added up to four unearned runs against left-hander Andy Pettitte.

St. Louis took the lead against Andy Pettitte in an odd third inning. After a pair of singles, Scott Spiezio grounded back to the pitcher for a potential double play. But second baseman Craig Biggio couldn't handle Pettitte's throw, and Carpenter scored on the error. Albert Pujols' bases-loaded double-play ball brought home the second run.

The Cards' third run came when Ronnie Belliard, doubled, took third on a balk and crossed the plate on a wild pitch. After Houston cut the lead to 3-2, Pujols' RBI single made it a two-run game. The Cards added on when Houston missed another chance at a double play as Spiezio scored on a Belliard groundout.

Yet that was all the Cards could muster, marking yet another game where they scored early but couldn't tally against an opponent's bullpen.

"When you have your best pitcher, one of the best pitchers in the game, and you score five runs, sometimes you say it's enough," said Pujols. "But obviously it wasn't. Chris made a couple good pitches, and maybe that last pitch kind of got away from him, but that's part of the game."

Pujols came up with some soreness in his hamstring on a play in the fifth inning, but said he expects to play Friday.