Mike Fontenot hit a solo homer and a two-run double and Derrek Lee had three RBIs to help Chicago shake out a mini-offensive slump that bridged the All-Star break.

Dempster (11-4) allowed six hits, all singles, and got his first road win since June 2, 2006, at St. Louis. He's 10-1 in 12 starts at Wrigley Field this season, but was 0-3 with a 4.03 ERA in eight starts away from home before Sunday.

"Such a relief," Dempster said with a smile. "All the questions can stop now."

The Astros had their four-game winning streak snapped.

The Cubs scored only four runs in their previous three games and batted .210 over that span. They had only one hit in their last 15 at-bats with runners in scoring position before getting two runs in the first inning against Houston starter Brandon Backe (6-10).

Kosuke Fukudome, in a 10-for-62 slump coming into the game, doubled to left with one out and scored on Lee's double to right-center. Jim Edmonds scored Lee with a single to center.

Ryan Theriot, who went 3-for-5 and extended his hitting streak to 13 games, said Houston's pitching deserved some of the credit for the Cubs' offensive woes in their first two games after the break.

"We ran into some tough pitching," Theriot said. "I don't really want to put all the blame on the offense. I don't buy into that too much. You've got to give the other guys credit. But it's good to score some runs and get a victory."

The Astros held a fan event on the field before the game and neither team took batting practice. Cubs manager Lou Piniella joked that his team may not take BP at all whenever they return to Houston.

"We'll make the bus 5:15 or 5:30, come out here and stretch and play," Piniella said.

Dempster allowed only singles by Carlos Lee and Lance Berkman in the first four innings.

Backe threw three perfect innings after the shaky first, but Fontenot homered down the right-field line with one out in the fifth to put the Cubs up 3-0. The second baseman has eight homers this season, six in his last 19 games.

Dempster only faced real trouble once, when the Astros loaded the bases with no outs in the fifth.

Miguel Tejada and Geoff Blum opened the inning with back-to-back singles. Hunter Pence hit a high bouncer to Theriot and the shortstop threw late to second, loading the bases for J.R. Towles, a .144 hitter. Dempster struck him out on three pitches.

Dempster then struck out Backe looking on a 3-2 pitch and Backe yelled at home-plate umpire Bill Miller as he stomped back to the dugout.

The fiery Backe was still steamed about the call after the game.

"To be honest, I saw the replay and it was just as bad as I thought it was," he said. "There's no telling what would've happened if he'd have called ball four. It would've been 3-1 with the top of the lineup coming up. Maybe we would've gone up 5-3. That was a big, big blow for us."

Kaz Matsui popped out to end the inning.

"We needed to score some runs in the worst way right there," said Houston manager Cecil Cooper.

After Theriot added an RBI single in the seventh for the Cubs, Cooper brought in Wesley Wright to relieve.

Dempster hit 100 pitches in the eighth, but still looked strong, striking out Matsui and Darin Erstad. He retired Berkman on a flyout to right.

Fontenot tacked on a two-run double in the ninth off Houston reliever Chris Sampson. The Astros bullpen had not allowed a run in 13 1-3 innings and Sampson had not given up a run in his last six appearances.

Fontenot scored on Theriot's broken-bat single to make it 7-0. Lee added a two-run single later in the inning off Chad Paronto, giving the Cubs their highest run total since a 9-2 win over San Francisco on June 30.

Notes: Berkman is 4-for-27 (.148) against the Cubs this season. ... Mark DeRosa made a diving catch on Matsui's sinking liner in the first inning. ... The Cubs have recorded a double in 18 consecutive games for the second time this season.