Clemens struck out seven in seven innings to get his 346th career win, leading the Astros over the Milwaukee Brewers 3-1.
Clemens (5-4) gave up six hits and one run to improve to 3-0 with a no-decision in his last four starts. He allowed just one runner past second base, lowering his ERA to 2.58, and threw 80 of his 108 pitches for strikes.
Astros manager Phil Garner was most impressed with Clemens' decision to pitch the seventh inning and save a weary, and struggling bullpen.
"What can you say about this guy?" Garner said. "I am continually amazed. ... There are just hundreds of pitchers out there you can't get another inning. They'll go out there and try it for you, but they don't get it done."
Clemens said he knew the significance of the seventh, in which he allowed a leadoff single before retiring the side in order and giving way to three relievers who did not allow another run. Dan Wheeler pitched the ninth for his fourth save -- a day after Houston pitchers combined to walk 11 and hit two batters in a 6-4 loss to Milwaukee.
"I knew ahead of time our guys have been used a lot out there in the bullpen," Clemens said. "I was just real fortunate to get the seventh under our belt, so we didn't have to use the guys too much."
Milwaukee's Doug Davis (9-7) yielded three runs and three hits in six innings to lose for the first time since July 9. He was 4-0 with three no-decisions in his seven previous starts.
Davis also walked Lane with the bases loaded in the first to put Houston in front 1-0.
"Walks will kill you," Davis said. "They hurt me today. Other than that, I threw pretty good. I got outpitched today. He pitched a great game. He is Roger Clemens, one of the best competitors in the game."
The Astros had lost seven of eight.
Clemens was coming off his worst outing of the season Tuesday, when he gave up five earned runs in six innings in a no-decision against the Chicago Cubs.
Against the Brewers, his only blemish came in the third, when Corey Hart hit his fourth home run of the season.
Clemens improved to 18-12 in his career against the Brewers and also singled in the seventh for his first hit of the season. Clemens started the year 0-for-17.
"What he does is he doesn't beat himself," Brewers manager Ned Yost said. "He makes you beat him with the bat. He was banging strikes and keeping the ball down."
Clemens said he was unaware of his ratio of strikes to balls.
"If I was that aggressive in the strike zone with the number of pitches, that's great," he said. "In a good game like this, the type of game it was breaking down to be, you don't want to offer any free passes."
The four walks hurt Davis, who entered play having given up the second-most walks in the National League. He walked two batters in the first and third innings.
Taveras led off the game with a single to center, extending his hitting streak to 23 games. Two batters later, Lance Berkman reached after Fielder dropped a chest-high throw from third baseman David Bell. The Astros went on to load the bases and Davis walked Lane to force in Taveras.
"That set up the whole inning," Yost said of Fielder's error. "We catch that, that doesn't happen. Sometimes it's tough picking up the ball with all the white shirts."
Both teams are 59-65 and five games behind NL wild-card leader Cincinnati. Houston travels to Cincinnati for three games starting Monday. The Brewers host Colorado for three.
"When we have a chance to get things done on the road, we need to do it," Clemens said. "In one sense, we're pretty fortunate to be where we're at. We're just like any other team right now. We're looking for that 12 out of 15 (wins)."
- After the game, the Astros designated backup C Eric Munson for assignment and recalled C J.R. House from Triple-A Round Rock.
- Astros RHP Roy Oswalt, scratched from his scheduled start Saturday due to a bruised right hand, is listed as day to day and will start Wednesday against the Reds, the team said.
- Brewers 2B Tony Graffanino had three hits to raise his average 20 points to .333.
- Brewers relievers have thrown 22 straight scoreless innings.