updated 1:32 a.m. ET Oct. 4, 2007

PHOENIX - Brandon Webb baffled the Cubs with his sinker, then staggered them with changeups and curves.

This high-stakes duel in the desert went to the quiet ace from Kentucky.

Webb shut down Chicago in a brilliant postseason debut, and the young Arizona Diamondbacks got home runs from two unflappable kids Wednesday night for a 3-1 victory in their NL playoff opener.

“You have your ace on the mound, you always expect to win that game, especially here at home,” Arizona manager Bob Melvin said. “It’s a game that was probably a little more pressure on us to win than them.”

Webb was locked in a tight game with Carlos Zambrano until Chicago manager Lou Piniella made a questionable move. He pulled his ace after only six innings and 85 pitches because he plans to bring the right-hander back on three days’ rest in Game 4.

Mark Reynolds promptly hit a tiebreaking homer off reliever Carlos Marmol, and the Diamondbacks held on behind their stingy bullpen.

Did planning for Game 4 cost the Cubs in Game 1? Piniella was terse when a reporter asked if he could be accused of looking ahead.

“I’m not accused of anything, sir,” Piniella said. “I’ve got a good bullpen here, OK? And I trust my bullpen. I’m bringing back a pitcher on three days’ rest on Sunday, and I took a shot with my bullpen. It didn’t work today. They’ve done it all year. I’ve got confidence in them — period, end of story.”

Game 2 is Thursday night, with Ted Lilly on the mound for Chicago against Doug Davis.

The Cubs, looking for their first World Series title in 99 years, had plenty of fan support — even on the road. The team holds spring training in nearby Mesa, and the valley is a popular retirement destination for Chicagoans.

In their first playoff appearance since losing Game 7 of the 2003 NL championship series to Florida, the Cubs managed little on offense. Alfonso Soriano, Jacque Jones, Aramis Ramirez and Cliff Floyd combined to go 0-for-16 with five strikeouts. Derrek Lee had a single but struck out three times.

Chicago twice got the leadoff batter to second with no outs early in the game but came away empty.

Webb, the reigning NL Cy Young Award winner, allowed four hits and struck out nine over seven outstanding innings. He walked three and hit a batter.

“I was able to keep them off-balance. I had pretty good stuff tonight, great off-speed,” Webb said. “Had some great strikeouts, key situations.”

Arizona setup man Brandon Lyon threw a perfect eighth, and closer Jose Valverde earned the save.

Stephen Drew homered in the fourth off Zambrano, who allowed four hits, struck out eight and walked one. Zambrano said he tried to talk Piniella into letting him go out for the seventh, but the pitcher would not criticize his manager.

“It was our manager’s decision,” Zambrano said. “We have a good bullpen.”

Right after Zambrano was lifted, Reynolds homered on the fourth pitch from Marmol to break a 1-all tie in the seventh. Pinch-hitter Conor Jackson added a sacrifice fly, and the Diamondbacks got two hitless innings from their bullpen.

“I’ve said all year that all of us young guys were kind of thrown in the middle of this. We really don’t know what’s going on,” said Reynolds, who started the season at Double-A Mobile. “We just go out there and do what we do, that’s play ball.”

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The showdown between 18-game winners was as advertised, with Zambrano matching Webb pitch for pitch through six innings with the roof open at Chase Field on a 91-degree night.

With Zambrano gone, the Diamondbacks went ahead in the seventh. Reynolds hit Marmol’s 2-1 pitch just over the left-field fence for a 2-1 lead. Chris Snyder walked and went to third on Augie Ojeda’s single before Jackson came through while batting for Webb.

Marmol had allowed only two runs in 25 innings after Aug. 10 for a 0.72 ERA.

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