ATLANTA -- Their fortunes having taken a turn for the better in recent days, the Astros will try to turn up the heat on Atlanta in Game 2 of the National League Division Series on Thursday night.

On Sunday, the Astros were just 12 outs away from having to go to Philadelphia for a play-in game. But after whipping Atlanta, 10-5, in Game 1 of the NLDS on Wednesday, the Astros are in an enviable position of having the series lead, and a chance to leave town with a 2-0 lead with seven-time Cy Young Award winner Roger Clemens ready to go in Game 2.

"We need to win one here, that's for sure," Atlanta manager Bobby Cox said. "I mean, it's pretty easy to shake off. We've got [John Smoltz] going tomorrow, [and] we scored five runs and played a real good game today."

They'll need a better one on Thursday.

Clemens makes his first postseason start after leading the Major Leagues in ERA. The Braves are in a must-win situation with the best-of-five series scheduled to move to Houston on Saturday.

"It's big, obviously, to win the first ballgame, but we've beaten the Braves the first ballgame before and lost," Astros first baseman Jeff Bagwell said. "We enjoy tonight, but it won't have any bearing on tomorrow. You've got two great pitchers out there who can throw zeroes the whole ballgame."

"It [the 1-0 lead] is nice, but they're not sitting over there panicking," Astros second baseman Craig Biggio agreed. "This series has a long way to go."

The Braves couldn't be in better hands.

Smoltz's 14 postseason wins are tied with Houston's Andy Pettitte, who won his 14th in Game 1, for the most playoff victories.

Smoltz and Clemens come in with a combined 24 postseason wins and 518 regular-season wins between them.

"If it was just about me facing him, and him facing me, we'd lead the world in strikeouts probably," said Smoltz, who finished the regular season 14-7 with a 3.06 ERA. "But, basically, when you go in the playoffs, names are one thing; credentials are another. And he has both. You know you're not going to get too much room to work with. My thoughts are, I better be on my game."

Clemens, 13-8 with a 1.87 ERA, has been bothered by a sore hamstring that caused him to miss a start. The right-hander returned on Saturday following a 12-day absence and pitched well in a win against Greg Maddux and the Cubs.

"I feel great, I got stronger," Clemens said. "My body -- I had what you would consider good soreness in the right areas, and my shoulder didn't pay the price for it. So when I was being treated, the person treating me said my hamstring was bad but my shoulder was almost -- equal, too, just because I was using a lot of arm those last three starts.

"I always have felt if I had a little problem with the elbow, shoulder, I can deal with it. My legs give out, I'm in trouble because I rely on them quite a bit."

First pitch is scheduled for 8:09 p.m. ET.