He worked out of trouble repeatedly Wednesday, allowing two runs on six singles and three walks in a 3-2 victory over the Chicago Cubs.

"I didn't know about Atilano, really. We didn't have a plan for him to be in the rotation," Nationals manager Jim Riggleman said. "He wasn't quite [as good as] he was against the Dodgers [in his April 23 debut] but ... he really kept his composure and battled."

Atilano's pitching has helped Washington to a 12-10 record, the franchise's best start since relocating from Montreal in 2005. A winning April is guaranteed -- and that's a big deal for a team that lost 103 games last season and 102 the year before that.

The Nationals even survived a week without injured star Ryan Zimmerman, who is expected back for the club's next game Friday.

"I know we're capable of playing this way, but it's so early," said Adam Dunn, whose fourth-inning homer snapped a 2-2 tie. "The positive thing is we still don't have our A-lineup. If we continue to get the pitching and play defense, we're going to be fine."

Atilano, who turns 25 in two weeks, pitched out of a one-out, bases-loaded jam in the fifth by retiring Marlon Byrd on an infield fly and Mike Fontenot on a grounder. After Fontenot's out, Atilano pumped his fist to celebrate.

"You've got to be pumped up," he said. "I don't care if I win the game easy or hard. I just like to win."

Brian Bruney, Tyler Clippard and Matt Capps each pitched one scoreless inning of relief. Capps earned his major league-leading 10th save in 10 attempts. Washington's bullpen has a 0.77 ERA in its last eight games.

Ryan Dempster (2-1) lost for the first time in eight career decisions against the Nationals-Expos franchise. He allowed only four hits and one walk in eight innings but each hit factored in the scoring: solo homers by Dunn and Adam Kennedy and second-inning singles by Roger Bernadina and Wil Nieves.

It was 2-2 in the fourth when Dunn put Dempster's 3-1 pitch into the left-field bleachers. Dunn has 41 homers in 409 career at-bats against the Cubs.

Twelve of Chicago's 22 games have been decided by two runs or fewer. The Cubs are 4-8 in those games -- a big reason they have a 10-12 record. They also are 1-9 when scoring three or fewer runs.

Manager Lou Piniella was upset the Cubs stranded 11 runners, and he got testy when asked if he considered having Fontenot bunt after Byrd led off the eighth with a double against Clippard.

"Bunting what? With a left-handed hitter up, you want to bunt? What kind of baseball do you play?" Piniella asked a reporter. "How about getting him in? Or getting him over by swinging? How about that?"

Fontenot popped out and Clippard didn't allow any more hits.

All five Cubs starters have sub-3.00 ERAs but the team still is having trouble winning. Nevertheless, Dempster refused to blame the hitters.

"Win a game 2-1 once in a while," he said. "I could have done a better job. I gave up a hit (to Nieves) with the pitcher on deck and I gave up a solo home run to a guy (Dunn) you don't want to let beat you. I've just got to be sharper next time."

Aramis Ramirez had a sacrifice fly, but the Chicago cleanup hitter is batting .155. And No. 3 hitter Derrek Lee has a .203 average.

"It doesn't help when I'm not getting on base and driving people in (from) the middle of the order," Lee said. "I have to start pulling my weight."

Game notes
Cubs CF Byrd lost Atilano's fifth-inning fly in the sun but still managed to make a no-look, behind-the-back catch while falling to his knees. ... Cubs SS Ryan Theriot had two singles and drove in the other Chicago run. He is batting .487 during an eight-game hitting streak, with multiple hits in seven of those games. ... The Nationals are 6-2 in games caught by Nieves. ... Kennedy was in a 2-for-20 slump before his first homer this season.