FLUSHING, New York (Ticker) -- Cliff Floyd knew he hit a big home run. Sammy Sosa just thought he did.

Floyd hit a two-run homer deep into the right field bullpen in the first inning to lift the New York Mets to a 4-1 victory over the Chicago Cubs .

Chicago opened the scoring with a run in the first but Roberto Alomar laced a one-out double of Cubs starter Matt Clement (0-1) in the bottom of the inning. Floyd followed with his first home run as a Met.

"I thought he was going to pitch around me a little bit with first base open," Floyd said of his former teammate. "But I didn't think I'd let a first-pitch fastball go."

Sosa, who is one homer away from 500 in his career, came up in the sixth inning with two aboard and the Cubs trailing by three runs. He sent Mets starter Al Leiter 's pitch high into the air and did his trademark celebratory hop-step, but Floyd caught the ball on the warning track in left field.

"He's trying to hit a home run sooner rather than later," Leiter said. "When he went into his little dance, I thought he had it."

Sosa hit his 497th homer off Leiter on September 17 of last season.

"Whatever happens, happens," Sosa said. "I wish I could get it over today. Sooner or later, I'm going to get it."

Sosa walked his first two times up and struck out leading off the ninth inning. His at-bat in the sixth was the only time that he went to the plate without first base open.

"They don't throw me strikes," Sosa said. "But sooner or later, they will make a mistake."

Clement made some mistakes, but left after the third inning due to injury. He experienced tightness in his lower back during that frame while pitching to Vance Wilson , but stayed on to complete the inning.

"We're treating it as if it's minor," Cubs manager Dusty Baker said. "I'm not a doctor, but if ready, he will go in his next start."

Before he left, Clement apppeared to be settling down in the wake of a rocky start. He uncorked three wild pitches in the first inning, but found his control after that and had retired the last four batters he faced before leaving.

"He had movement on his ball," Baker said. "He threw the ball well, but the lefthanded hitters gave him some problems."

One of those hitters, Roger Cedeno , homered to right-center field in the second inning.

Leiter (1-0) pitched six strong innings, allowing Chicago's only run on a bloop single by Moises Alou in the first inning. He allowed four hits and had three strikeouts.

Mike Stanton pitched a perfect eighth inning in his Mets' debut and Armando Benitez got the final three outs for his first save.

Former Met Mark Guthrie made his Cubs' debut and struck out the side in the fourth inning.