CHICAGO (AP) — Derrek Lee found his power stroke quickly this year.

Lee hit a tiebreaking homer in the seventh, Carlos Zambrano struck out seven in seven innings and the Chicago Cubs beat the Houston Astros 3-2 Sunday.

Lee connected against Oscar Villarreal (0-2) for his first third homer of the season. The Cubs first baseman 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.

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

Slumping Alfonso Soriano homered and made a great throw for the Cubs, and Zambrano (1-0) avoided the cramping that forced out of the season opener. He allowed two runs and seven hits with no walks.

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

Soriano was 1-for-24 this season when he lifted a 1-1 pitch from Brandon Backe over the left-field wall in the fifth to put the Cubs ahead 2-1.

He also bailed Zambrano out of a first-inning predicament by catching Carlos Lee's flyball and throwing out speedy Michael Bourn at the plate for an inning-ending double play.

Zambrano was forced to leave his opening-day start in the seventh with a forearm cramp. Also bothered by cramping last season, he'd 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.

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

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 Darin 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. ... Henry 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.