CHICAGO -- Despite being 20 games under .500 and with little to play for in the way of a postseason appearance, Phil Nevin and the Chicago Cubs haven't quit.
Nevin hit a three-run homer and rookie Carlos Marmol allowed one run over six innings to lead the Cubs to a 4-2 victory over the Houston Astros on Tuesday night.
The Cubs bounced back from an embarrassing 13-7 loss to the New York Mets on Sunday night, when they allowed 11 runs in the sixth inning.
"Obviously there is a lot of talk about it," Nevin said of the perception the Cubs have given up. "But we had some key injuries, and coming from a different organization to here, you lose your (No.) one and two starters, guys in the bullpen, and your first baseman who was a batting champion last year, you just don't replace those guys, it's impossible. But it's a team that's battled every day since I have been here and it's been enjoyable."
Marmol (3-3) gave up four hits, walked six and struck out six.
Ryan Dempster pitched a scoreless ninth inning for his 15th save in 20 opportunities.
Chris Burke homered for the Astros, who have lost six of eight and have matched their season low at four games under .500 (45-49).
"We just have to find a way to start playing more consistent and put a good string together of wins," Burke said.
The Cubs were trailing 1-0 in the fourth when Michael Barrett led off with a single. Two outs later, Jacque Jones singled and Nevin then hit a 2-2 fastball from Houston starter Roy Oswalt for his eighth homer of the season.
Nevin was traded to the Cubs on May 31 from Texas and has a total of 17 homers this season. He has homered twice in the last two games and has driven in five runs.
"That's generally a pitch I feel like, and I think Roy feels like, we can get him out with," Astros catcher Brad Ausmus said. "He did a nice job of foiling our plan."
Barrett doubled down the line in left in the fifth, scoring Ronny Cedeno and giving the Cubs a 4-1 lead. Barrett is 12-for-26 lifetime against Oswalt.
Oswalt (6-7) has gone six straight starts without a win and has lost his last four decisions, including a loss to St. Louis in relief on July 8.
Oswalt has had little run support all season. In six of his last 10 starts the Astros have scored two runs or fewer.
"As soon as he hit the home run I thought the game was over, 3-1," Oswalt said. "We have a tough time getting back into the game."
Marmol escaped trouble when he got Luke Scott to ground out in the sixth inning with runners on second and third.
"He made the pitches when he needed to and that was a big out he got there on Scott and it set the bullpen up the way you draw it up," Cubs manager Dusty Baker said.
Burke homered off reliever Scott Williamson in the seventh.
Marmol gave up a leadoff walk to Lance Berkman in the fourth inning and Aubrey Huff followed with a triple to right-center, giving the Astros a 1-0 lead.
Oswalt retired the first eight batters until giving up a two-out single to Marmol in the third inning. It was Marmol's first major league hit.
Greg Maddux and Roger Clemens are the scheduled starters for Wednesday's night game. The 300-game winners will face each other for the third time. They last faced on April 29, 2005, at Houston with Maddux the winner in Chicago's 3-2 victory. On June 3, 2000, neither was involved in the decision when Clemens was with the New York Yankees and Maddux was with Atlanta. ... Cedeno made a diving stop at shortstop and threw out Berkman in the seventh inning. ... Burke is 10-for-17 in his career at Wrigley Field.