NEW YORK -- The Josh Beckett gamble turned out to be pure genius.

The wild-card Florida Marlins wrapped up their wild ride with a most improbable World Series championship, stunning the New York Yankees 2-0 Saturday night behind the strong right arm and sheer determination of their young MVP.

Manager Jack McKeon was second-guessed the moment he said Beckett would start Game 6 on three days' rest. But the 23-year-old fastballer, called "Rook" by his manager, made McKeon look brilliant.

Starting on short rest for the first time in his career, Beckett threw a five-hitter to give the Marlins their second title in seven seasons.

"You'll believe me now that anything can happen," McKeon said. "This guy has the guts of a burglar."

Beckett outdueled Andy Pettitte and defeated a Yankees team that had won four of the last seven crowns, never allowing a runner past second base.

"That kid showed that he was going to be a great one down the road, if he hasn't already," Yankees manager Joe Torre said.

Not since 1981 had another team celebrated a Series championship on the field at Yankee Stadium. When the Los Angeles Dodgers did it then, Yankees owner George Steinbrenner apologized to the city for the dismal performance.

Yankees general manager Brian Cashman and former star Reggie Jackson, chins resting on hands, watched from a box with the same incredulous look on their face.

This time, credit the resilient Marlins for their performance. It was as if the sellout crowd of 55,773 couldn't believe what it was seeing -- then again, Florida has been an upset special this October in improving to 6-0 lifetime in postseason series.

The Marlins dropped the opener to Barry Bonds and the San Francisco Giants in the division before winning three in a row. They overcame a 3-1 deficit in the NL championship series, beating Cubs aces Mark Prior and Kerry Wood at Wrigley Field.

In this 100th World Series game at Yankee Stadium, Beckett and the Marlins never gave the Yankees much of a chance. Florida became the first team in the post-expansion era to win two titles, having joined the majors in 1993.

Beckett finished 1-1 in this Series. He lost Game 3 despite 7 1-3 impressive innings.

Luis Castillo snapped his 0-for-14 rut with an RBI single that saw Alex Gonzalez made a neat slide home in the fifth and Juan Encarnacion added a sacrifice fly in the sixth.

That was plenty for Beckett, who fielded Jorge Posada's tapper up the first-base line and tagged him for the final out. He struck out nine, featuring a 97 mph fastball, and walked two.

In the past five postseasons, pitchers working on three or fewer days' rest had been atrocious. In 37 such starts, they were 6-20 with a 5.93 ERA.

But Beckett and the 72-year-old McKeon threw that wisdom to the wind. It was just the kind of free thinking that made McKeon so successful this season -- the Marlins were 19-29 shortly after he took over for the fired Jeff Torborg in mid-May, and headed toward a last-place finish before he took them to the title.

"Nobody gave us a chance and here they are world champions," said McKeon, the oldest manager to win a World Series title.

Pettitte was sharp through the first four innings, working around an early double by former Yankees farmhand Mike Lowell.

Pettitte started strongly in the fifth, too, retiring the first two batters before the Marlins struck.

Gonzalez singled -- yet another hit from a ninth-place hitter whose bat is headed for the Hall of Fame, based on his 12th-inning homer in Game 4 -- and moved to second when Juan Pierre singled.

That brought up Castillo, only 3-for-23 in the Series, and he quickly fell behind in the count 0-2. Posada then made a trip to the mound to visit Pettitte and while the catcher and pitcher talked, on-deck hitter Ivan Rodriguez took several steps toward Castillo to shout some sort of encouragement.

Moments later, Castillo poked an opposite-field single to right and third-base coach Ozzie Guillen immediately waved Gonzalez home.

Right fielder Karim Garcia made a strong, one-hop throw to the plate that beat Gonzalez. But Posada, who almost always tries to avoid collisions, caught the ball a step up the first-base line and had to reach back on a swipe tag.

Gonzalez saw his opening and slid wide, reaching to touch the plate with his left hand as he tumbled past. It was a close play, but there was no argument for the Yankees as umpire Tim Welke called it correctly.

Down 1-0, the Yankees tried to rally in the fifth, putting a runner on second with two outs. Beckett took care of his nemesis with his fastest pitch of the night, a 97 mph fastball that Derek Jeter missed for strike three.

It was another missed chance for the Yankees, who were hitting just .149 (7-for-47) with runners in scoring position in the Series at that point.

Perhaps Jeter was still thinking about that key at-bat when Jeff Conine opened the sixth with a routine grounder to the All-Star shortstop. Jeter bobbled it and bounced his throw past first base for his first error in his last 27 Series games.

Florida took advantage of the error. After a walk and a bunt, Encarnacion lifted a sacrifice fly for a 2-0 lead.

Pettitte started the game by retiring Pierre on a popup -- right after a pitch grazed the leadoff man's jersey but was not called.

Beckett began his outing by striking out Jeter on three pitches.

Notes: New York is 64-36 in Series games at Yankee Stadium. ... Pettitte fell to 13-8 in postseason games. He remained tied with John Smoltz for the most postseason wins. ... The loss ended Roger Clemens' career. The Yankees pitcher is retiring. ... Castillo has not made an error in his last 82 games at second base.