The Mets ended nearly two decades of disappointment in their division and days of delay, clinching the NL East for the first time since 1988 with a 4–0 victory over the Florida Marlins last night.

Jose Valentin, one of their unexpected stars, homered twice and Steve Trachsel, their longest-tenured player, combined with three relievers on a four-hitter.

Fireworks shot off from behind the center-field wall when Cliff Floyd caught Josh Willingham’s fly ball to left for the final out. The Mets rushed to the center of the diamond to celebrate, hugging near shortstop.

New York’s “other team,” often obscured by the crosstown Yankees, had hoped to clinch last week during a trip to Florida and Pittsburgh. But the 280 or so bottles of Freixenet Cordon Negro Extra Dry sparkling wine that had been flown from city to city were neatly arrayed in four trays outside the clubhouse before the game, as if to tantalize passing players.

By the fifth inning, Pedro Martinez was sitting on the edge of the dugout, wearing goggles — perhaps in anticipation of sprayed sting in the celebration ahead. Perhaps remembering the wild celebrations of 1969 and 1986, police deployed four mounted officers on watch behind the right-field fence.

Led by the power of Carlos Beltran and Carlos Delgado, the pitching of Pedro Martinez and Tom Glavine, the spark of Jose Reyes and David Wright, and the closing of Billy Wagner, the Mets took over the NL East lead for good with a 2–1 record on April 6 and put together the best record in the major leagues (91–58).

Just two years removed from a 71–91 finish that led to the hiring of Omar Minaya as general manager and Willie Randolph as manager, the Mets ended the reign of the Atlanta Braves, who had won 14 straight division titles, including 11 in a row since their move to the NL East.

The Mets became the first team this season to clinch a playoff berth and can prepare for their first postseason appearance since 2000, when they won the wild card for the second straight season and lost to the Yankees in the World Series. The Mets are likely to meet St. Louis, Los Angeles or San Diego in the first round.

A giddy crowd of 46,729 chanted, clapped and sang at festive Shea Stadium — about 10,000 tickets were sold after Sunday’s loss completed a three-game Pirates’ sweep. Many arrived for batting practice, and fans already were on their feet cheering during the first inning.

Trachsel (15–7), who signed with the Mets, joined Gary Gentry (1969), Tom Seaver (1973), Dwight Gooden (1986) and Ron Darling (1988) as the only pitchers to win division clinchers for the Mets.

New York’s magic number for clinching the division had stayed stuck at one since Friday and by the time Valentin hit his first homer, the second-place Phillies already were losing 5–0 to the Cubs. Chicago took an 8–0 lead, but by the time of his second homer, Philadelphia had closed to 8–6.

Valentin hit a two-run homer in the third inning off Brian Moehler (7–9) following a walk by Shawn Green, a drive off the back fence of the Mets bullpen in right. He hit a solo shot to right in the fifth, earning his second curtain call of the night, and Floyd added an RBI single in the sixth against Renyel Pinto after an error by third baseman Miguel Cabrera.

Trachsel allowed three hits in 6.1 innings, struck out three and walked one before the bullpen took over.