ATLANTA - Randy Johnson has come a long way since his first no-hitter.

Back then, the Big Unit was just as tough to hit - he just wasn't quite sure where the ball was headed once it left his hand.

Now, at the ripe ol' age of 40, he has reached perfection.

Johnson became the oldest pitcher in baseball history to throw a perfect game, retiring all 27 hitters he faced in the Arizona Diamondbacks' 2-0 victory over Atlanta on Tuesday night.

''I've still got a great deal of pride,'' he said. ''I feel like I'm throwing as good as I've ever thrown.''

No kidding.

Johnson threw the 17th perfect game in major league history, the 15th since the modern era began in 1900 and the first since the New York Yankees' David Cone against Montreal on July 18, 1999.

''Everything he's done up to this point pales in comparison,'' Arizona manager Bob Brenly said.

That's saying a lot. Johnson has won five Cy Young Awards, put up all sorts of staggering strikeout numbers and helped Arizona win the World Series in 2001.

Now this, the rarest of pitching feats.

Johnson became the 27th pitcher to throw two no-hitters, and the nearly 14-year span between them was longer than anyone else. His first came for Seattle on June 2, 1990, when he no-hit Detroit but walked six.

''That was far from perfect,'' Johnson recalled. ''I was a very young pitcher who didn't have any idea where the ball was going. I was far from being a polished pitcher. Fourteen years later, I've come a long way as far as knowing what I want to do.''

Johnson struck out 13 and went to three balls on just one hitter - Johnny Estrada in the second inning. Estrada fouled off three straight 3-2 pitches before going down swinging.

Late in the game, Johnson sat stoically in the dugout, staring at the ground with his eyes closed, almost appearing to be asleep.

''It didn't faze me,'' the left-hander said. ''Winning the game was the biggest, most important thing.''

His manager was a lot more nervous. From the sixth inning on, Brenly remained frozen in the same spot - sitting on the bat rack, tapping Matt Kata's bat with his knuckles.

The other players were on edge, too.

''I tell you, man,'' outfielder Luis Gonzalez said, ''you get nervous when they're coming your way.''

Cy Young had been the oldest to throw a perfect game, doing it in 1904 at age 37.

Johnson sure didn't act his age, getting stronger as the game went along on a pleasantly warm night in Atlanta.

''Not bad for being 40 years old,'' he said. ''Everything was locked in.''

Curt Schilling, who teamed with Johnson to lead the Diamondbacks to the Series title three years ago, watched the final two innings on television in St. Petersburg, Fla. Schilling now pitches for Boston, which beat Tampa Bay 7-3.

''Guys that play the game at that level … do things other people don't dream of doing,'' Schilling said. ''They push themselves.''

Clearly, Johnson is back on his game after being hindered by a knee injury during a 6-8 season in 2003.

''I just want to find all those people that were talking about the end of his career last winter,'' Schilling said.

Johnson struck out the final batter, pinch-hitter Eddie Perez, with a 98 mph fastball.

''He could smell it at the end,'' Estrada said.

Johnson pumped his fist and raised his glove, but his teammates seemed a lot more excited. He started to put out his hand when Robby Hammock arrived at the mound, but the young catcher - a foot shorter than Johnson - gave the pitcher a bear hug instead.

Within seconds, Johnson was mobbed.