CHICAGO -- Watching from the clubhouse as the lead started to shrink, Roy Oswalt began to get that sinking feeling in the pit of his stomach.
Then, there was relief.
"I was standing in the corner of the bathroom a few times," Oswalt said. "But [Matt Lindstrom] did a real good job going out there and getting some quick outs, throwing strikes."
The Cubs scored three in the eighth and had the tying run on in the ninth after shortstop Tommy Manzella booted Ryan Theriot's two-out grounder. Theriot went to second on a wild pitch by Lindstrom, but Kosuke Fukudome struck out, giving the Astros their second win in three games after an 0-8 start.
Chicago's Tom Gorzelanny (0-1) gave up two runs in the second and left after being hit in the left arm by Pedro Feliz's line drive in the third. Alfonso Soriano had another tough day in left field, dropping a fly ball.
Towles raised his average from .056 to .182 with three hits and led off the fifth with his first homer. He also drove in two runs and scored twice.
A tough-luck loser in his first two starts, Oswalt (1-2) took sole possession of second place on the Astros' career wins list with his 138th victory and moved ahead of Larry Dierker, his first major league manager. He now trails Joe Niekro by six after striking out six without a walk, mixing a sharp change with his fastball.
"It means a lot," Oswalt said. "Dierk gave me the ball first day and told me, 'Pitch till you can't pitch no more.' It's been a lot of fun."
This, however, was anything but fun.
Brandon Lyon came on in the eighth and gave up a two-run double to left by Aramis Ramirez with one out, making it 4-2. Marlon Byrd then struck out before Soriano doubled down the left-field line to cut the lead to one. Chris Sampson then retired Mike Fontenot on a grounder to second to end the inning.
Lindstrom then converted his first save with a scoreless ninth.
Gorzelanny expects to make his next start against the Mets in New York after Feliz's liner in the third struck just below his pitching shoulder. The ball ricocheted toward first baseman Derrek Lee, who stepped on the bag for the second out.
Gorzelanny stayed in after a visit by the training staff, manager Lou Piniella and pitching coach Larry Rothschild, retiring Carlos Lee on a fly to deep left after throwing three warmup pitches. He was lifted for a pinch hitter in the bottom half, and Jeff Gray came on in the fourth after Gorzelanny lobbied to stay in.
"I pleaded my case and Lou wasn't having any of that," he said, adding that was "definitely" the right call.
On a shot like that, he said, "You just hope, no pray, you don't get hit in the face."
Gray allowed one hit in two innings, but it was a line drive by Towles off the left-field foul pole leading off the fifth. The Astros got another run in the seventh when Jeff Keppinger singled in Towles, and that was enough for Oswalt.
Houston finally gave him some run support after failing to score with him in the game during his first two starts.
"He's been throwing the ball well," manager Brad Mills said. "It's good to see him rewarded for it. He made some pitches when he had to and did a good job."
For the Cubs, it was a rough day.
Besides losing Gorzelanny, Soriano was hearing boos again after his latest mishap in the field. He was slow to come in on Jason Michaels' short fly with two out in the fifth and took his eyes "out of the glove" before dropping the ball for his third error of the season, this one coming after he made a neat catch on a liner to left-center the previous day. The double later on wasn't much comfort.
"It's not enough," he said.
The Astros held CF Michael Bourn out of the lineup for precautionary reasons because of a sore groin. He felt a tweak stretching for a ball in Wednesday's game at St. Louis. Bourn, batting .351, had a seven-game hitting streak snapped on Friday. ... Some Cubs fans serenaded Christopher Mintz-Plasse with a "McLovin" chant after he and several cast members from the movie "Kick-Ass" sang "Take Me Out to the Ballgame" during the seventh-inning stretch. Mintz-Plasse played "McLovin," a nerdy, eccentric character in "Superbad."