The Astros already knew they would have a chance to clinch the NL's last playoff spot on the final scheduled day of the regular season -- just like they did last year.
"I don't think that guys need to even concern themselves with if Washington is going to help us or not," Clemens said. "Just go out there and do it."
Clemens got a little run support and allowed one run in seven innings while pitching on a still sore left hamstring, leading the Astros over the Chicago Cubs 3-1 Saturday and putting Houston on the brink of a return to the playoffs.
After the Astros won, they knew their former closer, Billy Wagner, was on the mound for Philadelphia in Washington. The Houston clubhouse had pretty much cleared out before the Phillies wrapped up their 8-4 victory to remain one game back in the wild-card chase.
"It's good we still control our own fate, but we've got to take care of business tomorrow," Lance Berkman said.
Roy Oswalt (19-12) starts Sunday for Houston. But if the Astros lose and the Phillies win, Houston would go to Philadelphia for a one-game tiebreaker playoff Monday.
"Now, we sit back and watch Roy do his thing," Clemens said.
Jason Lane had an RBI single in the sixth that put the Astros ahead 2-1. That was plenty for Clemens (13-8), whose 1.87 ERA is the best in the major leagues -- and the lowest of his major-league career.
The Rocket skipped his previous turn in the rotation because of the hamstring, and the leg appeared to keep him from his sharpest. He allowed six hits and struck out five, including the 4,500th strikeout of his career, before being lifted for a pinch-hitter. It was the 341st victory of his career.
"There was no doubt that he could give this kind of performance, but you didn't know where his leg was going to be" manager Phil Garner said. "He had been working OK, but he was masterful again today."
Mainly because of poor run support, the 43-year-old right-hander had won just two of his previous nine outings.
Brad Lidge, whose blown save Friday night cost the Astros, worked a perfect ninth for his 41st save.
Craig Biggio hit the first pitch thrown by Jerome Williams (6-10) into the left-field seats for his 44th leadoff homer, extending his NL record and giving the Astros a 1-0 lead. Williams got out of the first when Lane popped out with two out, starting a stretch in which he retired 13 of 14 batters. He gave up three runs and six hits in seven innings.
"It was one of the best games I've ever had. ... I was going up against a guy that is an idol of mine," Williams said. "His stuff was good."
Chicago, at 79-82 assured of a losing record for the first time since 2002, got even in the fourth after Clemens gave up consecutive one-out singles to Nomar Garciaparra, Jeromy Burnitz and Michael Barrett. Matt Murton hit a sacrifice fly that sent Lane to the right-field warning track. Williams then took a called third strike, ending the inning.
Willy Taveras led off the Astros sixth with a double high off the left-center field wall, and came home on Lane's two-out single.
Clemens was in the on-deck circle when Adam Everett led off the seventh with a single. Chris Burke instead pinch hit, and got an infield single on his bunt that the Cubs hoped would roll foul. After Craig Biggio reached on a fielder's choice that retired Burke, Jeff Bagwell had an RBI-groundout.
"It was just another typical game. We play some nail-biters," Clemens said. "But you know that going in."
Houston has been held scoreless in nine of Clemens' 32 starts. Until this season, no pitcher had been shut out as many as eight times in a season since San Diego's Randy Jones in 1978.
Corey Patterson had an infield single to start the Chicago seventh, and Williams then had a sacrifice bunt. With major league batting leader Derrek Lee on deck with a runner at second, Neifi Perez hit into an inning-ending comebacker that Clemens knocked down and scrambled off the mound to pick up and throw to first.
"We had Roger in trouble a couple of times, but we managed only one run," Cubs manager Dusty Baker said. "Roger knows how to pitch, and he knows how to win."
The Astros had lost the first two games against Chicago, including 4-3 on Friday night after Lidge blew his first save in 25 chances since June 11 by giving up two runs in the ninth -- after Lance Berkman had hit a go-ahead, two-run homer in the eighth.
Lidge struck out the first batter he faced Saturday before two groundouts.
"Thank goodness I got another chance," Lidge said. "Obviously, I wanted to redeem myself."
- Clemens got his 4,500th career strikeout when he fanned Jose Macias for the second out in the third inning. The only pitcher with more is Nolan Ryan with 5,714.
- Lee went 0-for-2 with two strikeouts and two walks, but is still hitting .337. He is set to become the first Cub since Bill Buckner in 1980 to win a batting title. He is one hit shy of 200, a mark not reached by a Cubs player since Ryan Sandberg in 1984.
- Biggio's 44 leadoff homers are tied with Brady Anderson for the second-most in major-league history behind Rickey Henderson's 80.