Phoenix ? Somewhere in the desert, Randy Johnson must have discovered the Fountain of Youth.

The Big Unit, winner of three Cy Young Awards in three seasons with Arizona, threw a six-hitter as the Diamondbacks opened defense of their World Series championship by beating the San Diego Padres, 2-0, on Monday.

Arizona's Randy Johnson delivers during his six-hit shutout of San Diego. The Diamondbacks defeated the Padres, 2-0, Monday in Phoenix.

With a fastball that topped out at 100, the 38-year-old left-hander struck out eight and walked one to beat San Diego’s Kevin Jarvis.

“You saw his velocity up on the board,” San Diego’s Phil Nevin said. “Obviously, he hasn’t lost anything. He’s not old. He’s getting better with age.”

Mark Grace homered and made several tough plays at first, and Danny Bautista doubled in a run.

“Overall, I feel extremely good about the way I pitched,” Johnson said, “and the way everybody played.”

When Johnson last left the mound at Bank One Ballpark on Nov. 4, he had come out of the bullpen to get the final four outs in Game 7 of the World Series against the New York Yankees. Then he watched from the dugout as Arizona rallied with two runs in the ninth to win 3-2.

In a 30-minute pregame ceremony in front of a sellout crowd of 47,025, the World Series championship banner was unveiled high above the swimming pool in right-center field.

A giant replica of the World Series championship trophy was on display in center field, and Luis Gonzalez’s bloop single that drove in Jay Bell for the winning run in the ninth inning of Game 7 was shown on the giant screen.

Managing general partner Jerry Colangelo, whose decision to spend the young franchise deeply into debt brought the state of Arizona its first major sports championship, threw out the first pitch.

Although his strikeouts didn’t mount as they often do, Johnson induced the Padres into one ground out after another and recorded his 31st career shutout and 80th complete game. Johnson, 5-0 in 10 opening-day starts, pitched his first shutout in an opener, throwing 127 pitches.

Braves 7, Phillies 2

Atlanta Vinny Castilla hit a three-run homer and Gary Sheffield a hit a two-run shot. Tom Glavine, starting in place of the injured Greg Maddux, gained the win. He went six scoreless innings before tiring in the seventh and allowing two runs. Sheffield had an RBI groundout in the first and homered in the fifth.

Mets 6, Pirates 2

New York Newcomers Roberto Alomar and Roger Cedeno drove in runs with soft hits and Al Leiter allowed one unearned run in six innings to get the win. After finishing last in the majors in runs scored last season, the Mets revamped their offense, adding Alomar, Cedeno, Mo Vaughn and Jeromy Burnitz. The four new starters struggled, going 2-for-17 with nine strikeouts

Reds 5, Cubs 4

Cincinnati Aaron Boone hit a bases-loaded sacrifice fly in the bottom of the ninth off Jeff Fassero in the opener of the Reds’ final season at Cinergy Field. Right fielder Juan Encarnacion misjudged a fly ball, helping the Cubs rally for two runs to tie it in the eighth.

Cardinals 10, Rockies 2

St. Louis Albert Pujols, last year’s NL Rookie of the Year, broke open a tight game with a three-run double in the fourth inning, Matt Morris breezed and the Cardinals beat up on Mike Hampton. Mike DiFelice, who won the Cardinals’ catching job with a strong spring training, homered and drove in two runs as St. Louis played a regular-season game for the first time since Mark McGwire retired.