HOUSTON -- Monday may have been Carlos Zambrano's first win in five season openers, but the game wasn't about him. It might have been Alfonso Soriano's 50th career leadoff homer, but it wasn't about him, either.

Kevin Gregg did give up a run in the ninth but held on to notch his first save in his first game with the Cubs. But that's not what Zambrano will remember from the 4-2 win over the Houston Astros in the season opener.

"I feel happy," Zambrano said. "It's finally come true after five years [to win on Opening Day]. It's nice to have the win, especially for the team. One thing I was impressed with was Milton Bradley was 0-for-4, and he came in happy, and that's a good sign. Everybody was happy, people who went 0-for-4 and Kevin Gregg who gave up a run, he came in with the same attitude.

"That's important for the team. It doesn't matter what they did, they just care about the team. It's about teamwork."

Team Cubs began defense of the National League Central with a game that played out exactly as Lou Piniella planned -- the starting pitcher goes six, seven innings, the bullpen finishes up, and they get just enough hitting for the "W."

Any thought that Zambrano would throw another no-no against the Astros was squelched when Lance Berkman singled with one out in the second. Zambrano served up five hits over six-plus innings and struck out six in front of a Minute Maid Park record crowd of 43,827.

Why did it work this time and not the previous four openers?

"There was no emotion," Zambrano said. "It was one more game, that's it. I wasn't thinking today was Opening Day. I was not panicked, nervous. I was in control of myself and thinking it was another game. It's another game of my career, it's another game for the Chicago Cubs, just go out there and have fun. That's what I did today. Thank God everything was working today and I was able to do my job."

Soriano definitely helped, quieting critics who don't feel he should be leading off. He connected off Roy Oswalt (0-1), who was making his seventh Opening Day start. The left fielder is the first Cubs player to kick off Opening Day with a homer since Tuffy Rhodes connected off the Mets' Dwight Gooden on April 4, 1994. Aramis Ramirez then led off the Chicago second with a home run, the 250th of his career, to make it 2-0.

"That's what I've been doing for, how many years? Eight," Soriano said. "I'm very happy that Lou keeps me batting leadoff, and I'm going to try to do my job."

"That's why he's here," Zambrano said of Soriano. "He's a different leadoff hitter. You make a mistake to him or throw a first-pitch fastball, you know he'll be hacking. It's good to have Soriano in the leadoff spot and to be up 1-0. It's more relaxing for the pitcher to know you're up 1-0."

The Cubs didn't keep up that pace with a leadoff homer in the third, but did add on. Mike Fontenot had three hits and scored on Ryan Theriot's sacrifice fly in the fourth. Micah Hoffpauir added a pinch RBI single in the ninth.

"It's good when myself and Soriano go out and produce, but we've got nine players, eight players," Ramirez said. "Everybody has to do their part. It's not only 'Sori,' me or Bradley. Everybody has to produce for us to do what we did last year."

The defense definitely helped. The Astros had runners on first and second with one out in the first, but Kaz Matsui was caught in an embarrassing double play to help Zambrano get out of the mess. Catcher Geovany Soto threw out Tejada trying to steal second in the second. Ramirez helped Carlos Marmol out of a jam when he snared Carlos Lee's popup near the stands to end the eighth.

Tejada singled and Geoff Blum walked to open the Astros' seventh and chase Zambrano (1-0). Hunter Pence hit the first pitch from Aaron Heilman to ground into a big double play, but Tejada then scored on an infield hit by Michael Bourn that dribbled down the first-base line.

There was a moment of concern at the bottom of the seventh while "Deep in the Heart of Texas" was finishing up. Soto motioned to Piniella in the dugout, thinking the pitcher was suffering from cramps.

"I think 'Geo' is the one who has to have Lasik surgery," Zambrano said. "He was panicked, [is] what happened. This was his second Opening Day. He needs to get more mature."

"I talked to 'Z,'" Piniella said, "and he was OK."

So is Soto. And so is Bradley, who came up limping after hitting a popup to shallow right to end the eighth. He stepped awkwardly on first base, but had his ankle taped and stayed in the game.

There was one little glitch. In the seventh, the Cubs had a runner at first and one out, and Zambrano was up. He could have bunted.

"I don't know if 'Z' knows the bunt sign," Piniella said. "It'd be a good quiz."

"I don't know the bunt sign," Zambrano said. "There's no bunt sign for me. Two Silver Sluggers [awards]? Just kidding."

Remember that "team" thing?

"We started the season with a 'W,'" Ramirez said, "and that's all that matters."