CHICAGO -- If good things come in threes, the Houston Astros could be on the cusp of something big in the next few weeks.

Roger Clemens' return to the team is nearing, Andy Pettitte looked like the Pettitte of old in the series opener in Chicago, and Roy Oswalt made a convincing return from the disabled list Wednesday night, holding the Cubs to three runs over six innings in the Astros' 5-4 win before 39,946 at Wrigley Field.

Oswalt won for the first time since May 3, logging his second road win of the season and his first in exactly two months. But more importantly, his mere presence on the mound gave his team a big emotional lift, regardless of the outcome of the game.

"It's huge," Craig Biggio said. "He's one of the nastiest guys in the National League. That's a huge lift to get him back tonight."

In his first start since May 29, Oswalt allowed eight hits and walked none. He struck out two during his 90-pitch outing and would have liked to stay in for one more inning, but manager Phil Garner thought it best not to push the ace right-hander his first time back after fighting a back injury.

"He said if he tried to raise up the last couple of innings, he could feel it a little bit," Garner said. "He had a nice outing and then we got him out.

"He said he could go another inning. That wouldn't have been an issue. He was OK. It was my decision to take him out."

Oswalt allowed one run in each of the second, third and fourth frames. Garner thought the right-hander was being a bit tentative in the early innings, but it was a wet mound that appeared to be the issue.

"The first inning, it was really wet," Oswalt said. "I don't know if they covered the mound when it was raining [earlier in the day]. [Greg] Maddux was pitching on the other side of the rubber, and I was throwing on the first-base side of the rubber. I just kept sliding ... I finally got a hole dug and was able to stay in the same spot."

In the second, Oswalt yielded a leadoff double to Phil Nevin, who advanced to third on Aramis Ramirez's base hit and scored on a Jacque Jones sacrifice fly.

Ronny Cedeno knocked a leadoff triple off Oswalt in the third and scored on Maddux's grounder to short, and in the fourth, another leadoff hit -- this one a single by Michael Barrett -- turned into a run when Barrett advanced to third on Nevin's base hit and scored on a single by Ramirez.

Oswalt threw mostly fastballs early in the game, but as he became stronger, mixed in his breaking pitches. That likely helped him escape what could have been an ugly fourth inning, after three Cubs batters knocked consecutive hits.

Following Ramirez's RBI single to left, pitching coach Jim Hickey had a brief mound discussion with Oswalt, and the right-hander subsequently struck out Jacque Jones and induced a 6-4-3 double play from Matt Murton, preserving a 4-3 lead.

"At first, I was going right at them with the fastball and challenging them," Oswalt said. "After that, I started mixing it up a little more and got some guys out in front, got them off my fastball. I started mixing it up and starting showing I can throw a breaking pitch for a strike when I wanted to."

"His breaking ball didn't get better until maybe the fifth inning," Garner added. "That's a sign of just getting it done when you don't have your best stuff. You may be missing a pitch, but you still make it happen."

To the Cubs, it was the same old Oswalt, DL or no DL.

"Oswalt is Oswalt, he's a great pitcher," Matt Murton said. "I don't care what day it is. He hasn't won all those games by luck. The guy's a good pitcher, you have to battle against him and hopefully get enough runs to win the ballgame."

"For a guy just coming off the DL, who hadn't pitched in a while, he battled and made pitches when he had to," Nevin said.

The Astros scored five off Maddux. They tagged the future Hall of Famer for three runs on five hits in a second frame highlighted by an Adam Everett squeeze bunt, which scored Preston Wilson.

Maddux allowed a season-high 11 hits to the Astros, including two to Oswalt, who doubled and scored on Biggio's base hit in the fourth.

The Astros, 11-18 on the road this year, have won three of their last four road games and have secured their first road series win in nearly two months.

"The sign that's good is we've played good ball," Garner said. "We've played two nice ballgames. We need a nice ballgame tomorrow."