HOUSTON - Roger Clemens found himself alone in the bullpen.

"I don't really relish what those guys have to go through," Clemens said.

"Not a lot to do, flick seeds, chew gum, talk to the fans."

Until it was finally time to come to his team's rescue.

Clemens pitched a dominating three innings in his second career relief appearance before Chris Burke homered in the 18th inning to give the Astros a 7-6 victory over Atlanta on Sunday in the longest postseason game in baseball history.

"I love this, this is why you get off the couch to play this game," said Clemens, the 43-year-old ace who came out of retirement two years ago to pitch for his hometown club. "I've been fortunate to have played in a lot of big games, but it's still exciting."

Now, Clemens and Houston get another chance in the NL championship series against the St. Louis Cardinals - the same team the Rocket lost to in Game 7 last October to deny the Astros their first World Series appearance. It's the first NLCS rematch since Pittsburgh and Atlanta played in 1991-92.

Game 1 at Busch Stadium isn't until Wednesday night, giving the Astros time for some rest after the division series-ending game that lasted 5 hours, 50 minutes - and started only 14 hours after they won Game 3 on Saturday night.

"The game turned into a little bit of a three-ring circus," said Burke, a rookie who entered the game as a pinch-runner in the 10th. "Any time you play an 18-inning game, you want to win it."

The previous longest postseason game also was in Houston - the New York Mets won the 1986 NLCS with a 16-inning win at the Astrodome. Astros manager Phil Garner was a player in that game, and recalled a book written about it titled "The Greatest Game Ever Played."

"I think there's going to be a sequel," Garner said. "This is going to be the greatest game ever played. I can't imagine a better game with as much on the line as this game."

Maybe for Houston, but Atlanta made another early October exit, wasting Adam LaRoche's early grand slam and rookie catcher Brian McCann's homer.

The Braves were eliminated in the division series for the fourth straight year, and have just one World Series crown to show for their unprecedented 14 straight division titles.

"It never feels good, but I've had a couple of heartbreakers where I could have won the game, but instead ended the season," Chipper Jones said.

With the Braves up 6-1 in the eighth and poised to send the series back to Atlanta for a decisive Game 5 Monday night, Lance Berkman hit a grand slam in the eighth and Brad Ausmus tied Game 4 with a two-out homer in the ninth barely beyond Gold Glove center fielder Andruw Jones' outstretched glove.

It was about that same time that Clemens told Garner he was ready to pitch. By the 12th inning, the Rocket had his spikes and jersey on and was headed to the bullpen - waiting to be the Astros' eighth pitcher.

Clemens gave up one hit and struck out four of the 11 batters he faced in his first relief appearance since 1984, a measure of redemption for his poor start in Game 2.

"He did a remarkable job," Braves manager Bobby Cox said.

"He wasn't going to denied," Garner said. "I've never seen anybody like him."

Clemens actually entered the game as a pinch-hitter in the bottom of the 15th, and had a sacrifice bunt before Morgan Ensberg grounded into an inning-ending double play.

Batting just before Burke in the 18th, Clemens - who has never hit a home run in the majors - took a swing at ending the game with his bat. He "about fell down" against rookie Joey Devine before striking out.

Burke, batting for the third time since running for Berkman, then hit a 2-0 pitch over the left-field wall for only the sixth series-ending home run in history.

"Big moments like that always go by too fast," Burke said.