HOUSTON -- Lou Piniella decided to see what the youngsters could do for the Chicago Cubs.
And, they delivered.
"Colvin hit that ball in the upper deck, Hill had a two-run double," Piniella said. "It was a good game for those kids and it was a good game for us. We swung the bats good off of a good pitcher."
Aramis Ramirez also homered and drove in two runs for the Cubs, but it was Colvin and Hill who made a big difference while each making their 15th starts of the season. The loss ended Houston's four-game winning streak, tied for its longest this season.
"Colvin, we're going to play," Piniella said. "I've just got to move him around. I've got to be fair to everybody, but Colvin will be in the lineup most of the time as opposed to a few times."
Ryan Dempster (4-5), who had lost five of his last six decisions, allowed six hits and three earned runs over 6 1/3 innings. He struck out seven.
"It good to see the clutch hits, it was cool," Dempster said. "We went out there and tried to forget about everything before today. You can only control today's outcome. It's nice when guys put up a bunch of runs like that. Now we have a chance to win a series."
Oswalt (3-8) fell behind early on Ramirez's second-inning homer. Ramirez added a run-scoring single in the fourth, and a sacrifice fly by Alfonso Soriano gave Chicago a 3-2 lead after four innings.
"I felt real strong early, but it was a bad start," Oswalt said. "They pretty much hit everything that was over the plate. The guys came back and scored some runs for me early and made some defensive plays, but they kept hitting the balls over the plate."
Colvin hit his sixth homer in the seventh. Hill extended Chicago's lead with a two-run double in the eighth off Jeff Fulchino.
"I'm not going to hit too many home runs," Colvin said. "I'm not too excited about that, I just have to go out and help the team win. We got some big hits with men in scoring position. That's the thing we've needed to do. We'd get those men on, but we couldn't get them in. That's what we did tonight."
Jeff Keppinger extended his hitting streak to seven games with his first homer of the season in the third for the Astros. Humberto Quintero homered in the seventh and added a two-run double in the ninth.
Oswalt pitched seven innings and allowed nine hits, six earned runs and had one walk and one strikeout.
Lance Berkman had an RBI single in the first, but the lead held only until the bottom half, when Ramirez slugged his 269th career homer over the left-field fence.
Dempster had control problems in the first. He walked leadoff man Michael Bourn, who stole second and went to third on Keppinger's grounder. Dempster then went to a 3-0 count against Berkman, who singled up the middle to score Bourn. Dempster had a full count on Hunter Pence, who grounded out to end the inning.
Astros manager Brad Mills was impressed with the Cubs' offense.
"They probably saw the ball pretty well off him," Mills said. "Their two-through-five hitters were like 8 for 14 or something off him with a lot of extra-base hits. The thing was the extra-base hits. They got a couple home runs and doubles."
Piniella also liked what he saw.
"Ramirez had a good game, Derrek Lee had a good game," Piniella said. "We talked about the middle part of the lineup when they swing the bats. Today, they swung it and everything fell into place. Let's hope this is the start of something."
Lee and Soriano each need one home run to reach 300. ... Houston has the highest comeback percentage in the majors. They've rallied to win in 13 of their 21 victories, a .619 percentage. ... Hunter Pence ranks second in the NL with 12 infield hits. ... Oswalt started his 283rd game as an Astros pitcher, moving him into third place on the all-time list, one more than Nolan Ryan.