Chicago ? Mark Prior was nervous. After all, he was pitching in the playoffs for the first time and facing Greg Maddux.

“It was surreal to be in that dugout in the first inning and watch a guy I’ve watched my whole life growing up,” Prior said.

“Obviously there is nervousness and a little anxiety. You wouldn’t be human if you weren’t anxious in this situation. It’s the playoffs. You lose and you go home.”

It didn’t seem to bother him.

The 23-year-old right-hander threw a two-hitter and outpitched Maddux as the Chicago Cubs beat the Atlanta Braves, 3-1, Friday night to take a 2-1 lead in their best-of-five NL playoff series.

“I was looking forward to this game, win or lose. I knew it would be a learning experience,” Prior said. “I knew it would be a lot of fun and something you never forget.”

Prior again showed the poise of a veteran and shut down the NL’s top hitting club.

“He had great stuff and he’s really hard to hit,” Atlanta manager Bobby Cox said. “We didn’t hit that many balls hard. He was a little wild early and we didn’t take advantage of it.”

It was the first complete game by a Cubs pitcher in the postseason since Claude Passeau threw a one-hitter to beat the Detroit Tigers, 3-1, in Game 3 of the 1945 World Series.

“If you told me I would go out and throw a complete game, there is no way I would have thought that tonight,” Prior said.

“As Dusty (Baker) would say, the stars lined up and things worked out.”

Matt Clement will start today, when the Cubs try to capture their first postseason series since winning the 1908 World Series. Russ Ortiz, the Braves’ 21-game winner who took the loss in Game 1, will go on three days’ rest.

The Braves will need to wake up their bats and start catching the ball after making four errors Friday.

Atlanta led the NL in every major hitting category this season: batting average (.284), homers (a franchise-record 235) and runs (907, another club mark), but Prior was simply too good.

“This offense is very good, you’ve got to respect what they can do,” Prior said.

He yielded only Marcus Giles’ single to shallow right-center in the third and Mark DeRosa’s pinch-hit double leading off the eighth. Atlanta spoiled the shutout when DeRosa moved up on a groundout and scored on Giles’ sacrifice fly.

Prior, who won 18 games in his first full major-league season, walked four, struck out seven and was bolstered by a frenetic crowd at Wrigley Field.

“I tried to stay calm and focused and make pitches,” Prior said. “The crowd has been awesome all year.”

The Cubs got to Maddux in the first on Randall Simon’s two-out, two-run single that followed a key stolen base and wild pitch. Aramis Ramirez, acquired from the Pirates during the season just as Simon was, added a two-out RBI double in the eighth, and Prior made it stand up.