The Padres (23-36) roughed up Zambrano in the first inning on an RBI single off the bat of Adrian Gonzalez and a two-run triple by Kevin Kouzmanoff that, temporarily at least, put the Cubs' seven-game winning streak in peril.
But that's where the fun ended for the Padres, at least until Gonzalez hit a three-run home run in the ninth inning to cut the Cubs' lead to one run. Gonzalez has eight home runs and 25 RBIs over his last 16 games.
Gonzalez leads the National League in RBIs with 54.
"He's playing phenomenal," Padres manager Bud Black said. "He's really putting great swings on pitches he can drive. He's a hitter."
But the Padres managed only two more hits off Zambrano (8-1) in the four innings that followed, while their starting pitcher, Cha Seung Baek, was struggling to pitch his way through an offense that leads the Major Leagues with 331 runs (115 more than the Padres have scored).
"To get to a pitcher like Zambrano ... it's best to get him early like we did," Black said. "We couldn't break through after that inning. He wasn't on top of his game."
Neither was Baek, who was making his starting debut for the Padres. Baek didn't have the electric stuff he showed in a relief outing against the Giants on Friday, when he struck out the side in the 12th inning on just 12 pitches.
Baek, acquired from the Mariners on May 28, allowed hits to the first two batters he faced in the second inning and later gave up a run on a wild pitch. Baek allowed three more hits in the third inning, but he escaped trouble when Aramis Ramirez hit into a double play.
The fourth inning wouldn't be so kind to Baek, as he allowed a walk, the first of Jim Edmonds' two RBI doubles and an RBI triple to Zambrano, who pumped his fist after reaching the base.
"I made a couple of mistake pitches, wrong pitches, especially to Zambrano," said Baek, who yielded four runs on nine hits in 4 1/3 innings. "I hear he's a pretty good hitter."
Zambrano certainly wasn't the only one. Ryan Theriot (.325 average) had three hits, Ramirez (.315) had two hits and Japanese rookie Kosuke Fukudome (.305) got on base three times and scored two runs.
Even Edmonds, who was released by San Diego on May 9 after hitting .178 in 26 games, had two hits, including run-scoring doubles in the fourth and seventh innings that would prove important in the ninth inning when Gonzalez homered off Cubs relief pitcher Carlos Marmol.
"They're on a nice roll and swinging the bats well, playing with a lot of confidence," Black said. "They have a lot of guys hitting .300 or close to it."
What about the Padres? Gonzalez is hitting .298, and Brian Giles, who had a hit and a walk, is hitting .295. No other regular in the starting lineup is batting over .275.
"They had 14 hits, and seven of them the outfielders didn't even touch," Gonzalez said. "They found those little holes and came up with big hits and sac flies when they needed them. This season, things just aren't going well for us; they're going well for them."