Zambrano had his way with Cincinnati's slumping lineup, allowing only three hits in eight innings, and Ronny Cedeno singled home a pair of runs that sent the Cubs to a 3-0 victory on Tuesday night.
The Cubs won for only fourth time in 12 games, a span marked by inconsistency all-around. Zambrano (5-1) has been the guy they could depend upon.
"He's been great," said Kerry Wood, who pitched the ninth and finished off a four-hitter. "That's what aces do. They come in when you desperately need one, and we desperately needed one today."
The right-hander has won four straight decisions, two of them against a Reds lineup that is often its own worst enemy. Cincinnati got only one runner to second base in the first five innings -- Joey Votto, who was picked off by Zambrano.
"Every team passes through some slumps," Zambrano said. "That's normal. We're doing the right things, but we've kind of slowed down. We need to put everything together."
Zambrano gave up three singles and three walks, struck out three and lowered his earned run average to 1.80. Wood, pitching on the 10-year anniversary of his 20-strikeout game, gave up a bunt single and struck out two in the ninth, getting his fifth save in eight chances.
The most encouraging sign for the Cubs: They won a game without much from their offense. Chicago has the majors' most prolific offense, but has too often been an all-or-nothing attack.
The Cubs are 16-1 when they score four or more runs, only 3-13 when they get less.
"We won with three runs," manager Lou Piniella said, breaking into a smile. "Let's see if we can do that a little more often."
For the Reds, just scoring a run is a huge task these days. They were shut out for the third time this season, half their total last year. They've lost six of their last seven overall, struggling no matter who's in the lineup or who's on the mound.
"I know you guys are just as dumbfounded as I am right now," said Aaron Harang (1-5). "This team is a lot better than the way we've been playing."
No one has suffered from the Reds' weak offense more than Harang. The right-hander gave up three runs and seven hits in six innings, leaving his earned run average at 3.33.
In half of Harang's eight starts, the Reds have scored two runs or less.
"It's tough for Aaron," manager Dusty Baker said. "You know he's going to get on a roll, but that doesn't help now."
Third baseman Aramis Ramirez was back in the Cubs' lineup after missing three games with a sore left wrist, which was hit by a pitch on Friday. He had a run-scoring single in the first inning, a ball hit sharply up the middle that made it 1-0.
A pair of walks and a sacrifice left Cubs at second and third with two outs in the fourth inning -- Cedeno's best situation. He slapped a down-and-away breaking ball into right field for a 3-0 lead.
"I gave up those two walks, and the guy flips a little base hit where nobody is," Harang said. "If anybody's got a horseshoe, please give it to us. I had him set up to do that, and he just hits it where we're not."
The utility infielder has been one of Chicago's best clutch hitters. Fourteen of his 18 RBI have come with two outs, the most on the team.
Before the game, Piniella singled out the team's defense as a main area for improvement. Two errors gave Cincinnati five unearned runs in the series opener, a 5-3 win on Monday night.
The Cubs had two more errors on Tuesday, but Zambrano didn't let them hurt him. Nothing could get him off his game. He induced Edwin Encarnacion to ground into a double play in the sixth, scuttling a rally set up by one of the errors.
Ken Griffey Jr. had a pair of singles off Zambrano, but remained at 597 career homers. Griffey plans to attend a memorial for one of his boyhood friends in Orlando, Fla., on Thursday, the team's day off.
- Cubs C Geovany Soto extended his hitting streak to eight games.
- The Reds released LHP Scott Sauerbeck, who was pitching for Triple-A Louisville. The reliever was 0-1 with a 9.00 ERA in four appearances.
- Encarnacion went 0-for-4 snapping a streak of 25 straight games in which he had reached base safely. He did reach on an error by 1B Derrek Lee in the fourth, but that doesn't count toward the streak.