Oswalt knew he was done after nine innings against the Philadelphia Phillies on Tuesday night. The right-hander was headed to the clubhouse with the game tied.
"I actually had a funny feeling as I was walking back," Oswalt said. "I thought, wouldn't it be great if we had a walk-off homer. Then I looked up on the TV screen when I got to the clubhouse and Mike had done it."
Lamb hit his sixth homer of the season leading off the bottom of the ninth to give the Houston Astros a 2-1 victory and move Oswalt into a tie with St. Louis' Chris Carpenter for the National League lead for wins.
Oswalt (14-8), who improved to 10-1 at home, leads the majors in wins since the 2004 All-Star break with 26.
Oswalt, who has taken the decision in every start this season, won for the eighth time in his last nine games and dropped his ERA to 2.33, third in the NL. He allowed eight hits and struck out nine, walking four.
"It was Roy's best game of the year," Astros manager Phil Garner said. "He was going to his fastballs up in the zone and his sliders down."
Garner went out to check on Oswalt with two outs in the top of the ninth after Ryan Howard had singled to put runners on first and second.
"I just wanted to see how he felt," Garner said. "If he says he's OK, I'm going to let him go get 'em and he did."
Oswalt didn't want to come out then.
"I felt strong," he said. "That's one reason I wanted to stay in. He asked me if I felt strong and I said 'Yes.' I had gotten (David Bell) out all night and I wanted to face him."
Bell, who finished 0-for-4, hit a fly ball to deep right center field to end the inning.
That set up Lamb's big hit off reliever Ryan Madson (4-4), who took the loss on only his second pitch.
"(Madson) throws 93 or 94 miles an hour," Lamb said. "I've got to sit on the fastball and try to adjust to the off-speed pitches. You can't go the other way on him. He threw me the fastball."
Madson had no excuses.
"I was just trying to throw a strike," he said. "I didn't want to walk him. It was supposed to be outside but it came back over the plate."
The Phillies thought starter Jon Lieber, who went seven innings and allowed one run and six hits with no walks and four strikeouts pitched as well as Oswalt.
"It's a shame the game had to end this way," said bench coach Gary Varsho, filling in for manager Charlie Manuel who missed the game due to a death in the family. "It was a very well-pitched game but the little things mean so much in a close game. We had opportunities to score. We just didn't execute. We have got to find ways to score runs on the road.
"Oswalt did a great job of staying ahead just like our guy. It seemed like every first pitch was a called strike."
The Phillies praised Oswalt.
"I think he definitely deserved to win the game," Phillies catcher Todd Pratt said. "Both teams played hard and he went the full nine.
"It's the first time I've faced him and to understate the obvious, he's very good. It's amazing for a guy who's really not that big size-wise. But he is so strong."
Lieber is 1-5 with three no-decisions in his last nine starts.
"It's been a frustrating 2½ months for me personally," he said. "But I've been getting much better by keeping the ball down for the most part. My hanging slider to (Craig) Biggio obviously was a mistake.
"These last two starts, guys on the other team have really pitched better and I have to tip my hat to them."
Houston has won nine of its last 10 and 21 of 28. Philadelphia has lost eight of it last 11 road games.
Ugueth Urbina pitched a scoreless eighth inning, running the Phillies' bullpen streak of shutout innings to 14.
Biggio started the scoring with his 16th home run in the first inning. It was his third in two games and the 250th of his career.
- Astros 32-14 record at home is the best in the major leagues.
- In the third inning, Willy Taveras got his major-league leading 50th infield single on a hit that Lieber knocked down, then couldn't find as it dribbled behind him. Taveras tied the club record set by Biggio in 1992.
- Manuel missed his second game due to the death of his sister, Janet, in Virginia. He is expected back for Wednesday's game.
- Phillies have the best fielding percentage in the majors (.987) and the fewest errors (50).