CHICAGO (AP) - Derrek Lee had another big hit for the Chicago Cubs , and he was more interested in talking about teammate Alfonso Soriano 's play in the field.

Lee hit a tiebreaking homer in the seventh and Soriano threw out a runner at the plate to help the Chicago Cubs edge the Houston Astros 3-2 on Sunday.

''A huge play,'' Lee said of Soriano's perfect strike that cut down speedy Michael Bourn and completed a double play that ended the first inning.

''It kind of turned the momentum to our side. It could have been a big inning. ... But that double play really got us doing.''

Bourn led off with a single and made it to third on a double by Hunter Pence . Carlos Zambrano fanned Darin Erstad before Carlos Lee lifted a fly to left and Soriano made a perfect throw to catcher Henry Blanco . Soriano had 19 outfield assists last season.

''I think somebody has to see the scouting report. Soriano is one of the best throwing. He proved it last year,'' said Zambrano, who struck out seven in seven innings.

For the Astros, it was a risk but also a chance to score early against Zambrano, who'd been forced out of the season opener with a forearm cramp.

''You have to try. You've got 'Z' on the mound,'' Astros manager Cecil Cooper said, adding that he didn't fault third-base coach Ed Romero 's decision to send Bourn.

''The one thing I told my third-base coach was to be aggressive. ... It has to be a perfect throw.''

And it was.

''Sometimes when you are having a problem with hitting, you have to play defense and that's what I tried to do,'' said Soriano, who also hit his first homer Sunday but is just 2-for-26 this season.

Lee connected against Oscar Villarreal (0-2) for his third homer of the season. The Cubs first baseman, who went 4-for-4 Saturday, finished 2-for-3 with a walk and his one out was a long fly to deep center. He didn't hit his first homer last season until the 21st game and finished the season with only 22.

He's 10-for-25 so far and six of his hits have gone for extra bases.

''I feel good. It's only a week in. I'll just try to maintain it,'' Lee said. ''We got a long way to go. You have to go out and have good at-bats every day.''

The Astros had tied it when Miguel Tejada hit his first homer with Houston leading off the seventh.

Zambrano (1-0) allowed two runs and seven hits with no walks. Also bothered by cramping last season, he was been advised by the team's training staff to cut back on his pregame caffeine intake and drink more water. He threw 105 pitches against Houston.

Although Zambrano said he didn't have a banana Sunday, he ate plenty of them Friday and Saturday to get his body ready after tests revealed a low potassium level.

''More than one,'' he said. ''I feel like a monkey now.''

Kerry Wood pitched a perfect ninth for his third save in as many chances, striking out Tejada to end it.

Soriano lifted a 1-1 pitch from Brandon Backe just over the left-field wall in the fifth to put the Cubs ahead 2-1.

''I thought I had him off balance all day. Literally I had him off balance on that pitch,'' Backe said. ''If it wasn't for the basket, it probably wasn't going out. With that said, it's a pitch I can't have him hit. It's got to be in the dirt.''

Backe went six innings, giving up six hits and two runs with three walks and seven strikeouts.

Zambrano's bases-loaded double play grounder put the Cubs ahead 1-0 in the second. The Astros tied it when Erstad's two-out single in the third scored Backe, who led off with a flyball double to right that got behind Kosuke Fukudome .

The Cubs loaded the bases with one out in the fifth but Backe escaped by striking out Mark DeRosa and getting Ryan Theriot to ground to shortstop.

Notes: Bourn jogged to first thinking he'd walked on a check swing 3-2 pitch in the eighth. But after Cubs manager Lou Piniella came out of the dugout and asked for an appeal, third-base umpire Kerwin Danley ruled Bourn went around and was out. ... Blanco got the start at catcher for the Cubs, who rested Geovany Soto and gave him a chance to practice using his legs to aid his throwing motion. Base stealers are 7-for-7 against Soto this season. ... Houston 1B Lance Berkman (neck spasms) and 3B Ty Wigginton (small fracture in his left thumb) did not play. They both left Saturday's game early. Wigginton will be examined Monday. ... Astros 2B Kaz Matsui, on the disabled list after problems with an anal fissure, is scheduled to go on a rehab assignment with Double-A Corpus Christi starting Tuesday.