SAN DIEGO (AP) – With one swing of Albert Pujols’ bat, a St. Louis Cardinals lineup that looked so sickly in September suddenly got a lot better under the California sun.

San Diego Padres ace Jake Peavy tempted Pujols with one pitch too many and the slugger, who has a shot at a second straight NL MVP award, responded with a two-run homer that launched the Cardinals to a 5-1 victory in the opening game of the division series on Tuesday.

While Peavy struggled – he left to a mixture of boos and light applause in the sixth – St. Louis ace Chris Carpenter, the reigning NL Cy Young winner, held the Padres’ suspect offense to one run and five hits in 6 1-3 innings. He struck out seven and walked one.

Even with a change of scenery, San Diego still can’t beat the Cardinals in October. The three-time NL Central champion Cardinals have won seven straight postseason games against the Padres, including division series sweeps last year and in 1996.

Overall, the two-time NL West champion Padres have lost eight straight postseason games dating to 1998, when they were swept in the World Series by the New York Yankees.

The Padres came into this series more confident and healthier than the Cardinals, who backed into the playoffs after barely avoiding one of the worst September collapses ever. The Padres even had home-field advantage for the first time in a postseason series since opening the 1984 World Series in San Diego.

Peavy was hoping for far better results than Game 1 of last year’s playoff series, when he lost 8-5 to Carpenter at St. Louis while pitching with two broken ribs. Peavy hurt himself when he jumped on Trevor Hoffman’s head while celebrating the Padres’ division title several days earlier.

Pujols, though, reminded the Padres just how dangerous of a hitter he is. Peavy left a full-count cut fastball over the plate and Pujols drove it an estimated 422 feet into the Padres’ bullpen beyond the fence in left-center to break a scoreless tie in the fourth inning.

Center fielder Mike Cameron climbed halfway up the fence in a futile effort at Pujols’ 11th career postseason homer, which hushed the sellout crowd of 43,107 at Petco Park. Chris Duncan was aboard on a leadoff single.

The eight-pitch at-bat was kept alive when catcher Mike Piazza got a late jump on Pujols’ foul pop and couldn’t catch it at the screen.

Pujols hit a three-run homer off Padres rookie reliever Cla Meredith last Wednesday in a 4-2 win at St. Louis that may have saved the Cardinals’ season. St. Louis lost nine of its last 12 regular-season games.

Following Pujols’ homer, Jim Edmonds singled, Scott Rolen doubled and Juan Encarnacion hit a sacrifice fly.

Carpenter was pitching for the first time since losing 7-5 to the Padres at St. Louis a week earlier. Cardinals manager Tony La Russa gambled on Sunday and held Carpenter out of the regular-season finale in case the right-hander would have been needed Monday in the makeup of a rainout against the Giants. But that became moot when Atlanta beat Houston, giving the Cards the NL Central title.

Down 5-0, San Diego finally broke through against Carpenter in the sixth. Dave Roberts legged out a one-out triple to the left-center gap, his third hit, and scored on Brian Giles’ sacrifice fly.

The Padres had two big scoring chances and came away empty, including loading the bases with one out in the seventh.

Russell Branyan tripled and Mike Cameron walked to chase Carpenter in the seventh. Reliever Tyler Johnson hit pinch-hitter Josh Bard on the foot with his first pitch to load the bases, then struck out pinch-hitter Mark Bellhorn and got Todd Walker to ground out to end the inning.

Carpenter got out of a jam after Roberts and Giles opened the fourth with singles. Carpenter struck out Adrian Gonzalez and got Piazza to force Giles, which moved Roberts to third, before striking out Branyan.

Edmonds hit an RBI single for the Cardinals in the fifth and Yadier Molina’s RBI basehit in the sixth gave St. Louis a 5-0 lead and chased Peavy.

Peavy allowed five runs 11 hits in 5 1-3 innings, struck out two and walked one.

Notes: All the Cardinals regulars except David Eckstein had a hit off Peavy. Carpenter had a single, too. … Ryan Klesko made San Diego’s postseason roster even though he missed all but the last 11/2 weeks of the season after undergoing surgery on his left shoulder in April. He pinch-hit in the ninth and hit a fly ball for the final out. … RHP Chan Ho Park made the postseason roster, too, despite missing much of the last two months after two bouts with intestinal bleeding that required surgery on Aug. 23. Park pitched the eighth Tuesday.