The Astros were one strike away from a series-clinching win before St. Louis rallied for three runs on a home run by Albert Pujols off Houston closer Brad Lidge that kept the Cardinals alive in the best-of-seven series.
Houston leads, three games to two.
"Give them credit, that was a big-time situation to hit that pitch," Astros left-hander Andy Pettitte said of Pujols. "That's why he's one of the best hitters in the game, probably is the best hitter in the game."
The same two starters from Game 2, Houston right-hander Roy Oswalt and St. Louis lefty Mark Mulder, will face each other in Game 6.
"We've got Roy on the mound on Wednesday, and I hope Lidge goes out there and gets another chance to save the game," Houston shortstop Adam Everett said. "He's one of the best in the game, and we've got every confidence in the world in him."
The Astros, now 0-5 in potential NLCS-clinching games, can earn a berth in what would be the first World Series appearance in franchise history with one more win.
The Cardinals are attempting to become the third NL team to overcome a 3-1 deficit in a seven-game series in the NLCS. The Marlins did it in 2003 and the 1996 Braves also accomplished such a comeback.
"Game 6 they've got Roy, we've got Mark, a classic matchup," St. Louis manager Tony La Russa said. "But we're back at Busch, and we're going to do exactly what we did [in Game 5]. The guys coined the phrase, 'Hard nine.' We're going to play a hard nine. If feels different from last year, because everything is different, but the matchups are real exciting."
Last year, the Astros went back to St. Louis leading, 3-2, in the NLCS, but lost both games as the Cardinals advanced to the World Series, where they were swept by the Red Sox.
Houston started Pete Munro in Game 6 last season and Roger Clemens in Game 7. Should it go the distance again, Clemens would start against Cardinals right-hander Matt Morris.
The Astros said the way they lost Game 6 won't carry over to St. Louis, and scoffed at the notion the momentum of the series may have shifted.
"Momentum is as good as your next day's starter," Houston second baseman Craig Biggio said. "We've got Roy and they've got the lefty. It should be a hard battle just like it was [in Game 2]."
"No question in mind that we'll bounce back and play well," Houston manager Phil Garner said.
Jim Molony is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.