ATLANTIC CITY, N.J. — Moments after he had outpointed Joshua Clottey in Saturday night’s co-feature at Boardwalk Hall, Antonio Margarito expressed his desire to fight the winner of the Miguel Cotto-Carlos Quintana main event that was about to enter the ring.

Half an hour later, if he is as smart as we think he is, the WBO champion might have been rethinking that challenge, for Cotto’s debut as a 147-pounder was an impressive one indeed, as he floored Carlos Quintana twice in the fifth round with a paralyzing body attack that sent his heretofore undefeated Puerto Rican countryman back to his stool dazed and unable to continue.

The fifth-round TKO earned Cotto the World Boxing Association title recently vacated by Ricky Hatton, and left Cotto (28-0) calling out the rest of the world’s welterweights — including, but not limited to, Tony Margarito.

Although Cotto was the aggressor throughout, Quintana was able to use his superior reach to fight back, and after four rounds all three ringside judges (Glenn Feldman, George Hill and Malvina Lathan, who was subbing for the ailing Julie Lederman) had it even at 38-all (The Sweet Science had Cotto up 39-37), but the roof came crashing down on Quintana in the fifth.

In addition to the 7-pound leap in weight, one of the questions going into the bout concerned Cotto’s ability to handle the Quintana’s southpaw style. Quintana’s stance never seemed to bother Cotto at all, but when the latter switched to southpaw early in the fifth it appeared to give the surprised Quintana problems.

During the pre-fight introductions, the allegiance of the crowd, announced at 7,412, appeared to be divided nearly 2-1 in Cotto’s favor, and he seemed to have won over new converts as the bout progressed.

By the fifth chants of Cotto’s name rocked Boardwalk Hall, and any residual vestige of support for Quintana, who had by then twice been warned by referee Steve Smoger for low blows, had become decidedly muted.

Late in the second minute of the fifth, Cotto ripped into Quintana with a hard left to the body. Cotto would say later that he had targeted Quintana’s liver, but if so, either his aim was bad or his anatomical knowledge leaves something to be desired, because the shivering punch actually caught the opponent high on his right side.

The effect, on the other hand, was devastating, Quintana crumpled straight to the canvas in evident pain, and when he arose could barely defend himself. Cotto backed him into a corner and landed two more right hands before firing another left to the body.

Quintana took Smoger’s count on his knees, and was barely able to hoist himself to his feet in time to beat it before he was rescued by the bell ending the round.

Dr. Dominic Coletta, the ringside physician assigned to the Quintana corner, studied his patient carefully between rounds, and appeared to be unimpressed. Then, just before the bell would have sounded to open the sixth, New Jersey commission chairman Larry Hazzard came racing, like a man possessed, across the ring to Quintana’s corner, and the fight was over.

Officially, the bout was stopped by Smoger on Coletta’s advice.  (Almost immediately, the referee leaned over and gently kissed Quintana where he sat on his stool.)

“The corner wanted to let him continue,” said Dr. Coletta, “but I could tell the fighter did not. I saw hurt in his eyes.” (And rage, apparently, in Hazzard’s.)

“Miguel is very fast, and he hit me pretty good,” Quintana, now 23-1, said afterward through an interpreter. “I couldn’t handle his speed, and that surprised me.”

“Every punch I threw was hard,” said Cotto. “I felt very strong at this weight. I can do anything I want to do.”

“Miguel,” said Evangelista Cotto, the new champion’s trainer and uncle, “can destroy every fighter in this weight division.”

If Margarito was supposed to make a case for himself as the iron of the welterweight division, he came up short, but he did capture a unanimous decision in a fight that was certainly closer than Gene Grant’s preposterous118-109, and may well have been closer than the 116-112 margins tabulated by the other two judges, Paul Venti and John Stewart.

Although Margarito, by his own admission, “couldn’t get my rhythm early,” this fact escaped the judges, and all three gave the first round to the Mexican champion. (Most scribes scoring at ringside gave it to Clottey.) The Ghanaian won the next two stanzas on all three cards, and the fourth on Venti’s and Stewart’s, as well as ours.

During the fourth, however, Clottey severely injured his left hand, in all likelihood fracturing the knuckle of his index finger. Although he continued to use the hand, the confident aggression he had displayed over the first four rounds all but disappeared.

There had also been a clash of heads at the end of the fourth, and Clottey, the instigator, returned to his corner having apparently gotten the worst of that, too.

Margarito, in any case, was a changed boxer as the fifth began, initiating a body attack that would carry on for most of the rest of the night. As Clottey’s fortunes ebbed, his corner began flashing animated signals confirming the damaged hand, and during one lull in action Clottey himself leaned over the ring ropes and pantomimed a gesture to the television crew below, indicating that he had hurt his paw.

Since this is normally the sort of information a wounded boxer would rather his opponent not know about, Clottey, perhaps subconsciously, may already have been in the process of preparing his excuse.

Margarito, if he was aware of the injury to his opponent, didn’t have long to enjoy it. In the sixth he damaged his own right wrist.

Then Clottey, or so he claimed, “broke,” or at least injured, his right hand in the seventh.

Margarito continued his inexorable march, with two notable exceptions: Clottey spent most of the tenth running, but he did interrupt his retreat long enough to land a few punches. Margarito barely bothered throw any, but all three judges rewarded his exasperation by giving him the round anyway.

And Margarito hardly looked like a champion defending his title in the final stanza, a round he essentially gave away to Clottey and lost on two judges’ cards.

Clottey said that the damage to his hands, especially the left, hampered his performance.

“I couldn’t jab, and I use my left to set up my body shots and combinations,” said Clottey.

Well. Who doesn’t?

How severe Clottey’s injuries actually were, and how much they affected him, remains unlearned, but they probably didn’t affect the overall result: Even giving the challenger the first four, the 10th, and the 12th, our scorecard came up level at 114-114, so even in our favorable view Margarito would have retained his title anyway.

It was at the very least a courageous performance by Clottey, now 30-2, and a workmanlike if unspectacular win for Margarito, 34-4.

“I’ve been off for ten months,” said Margarito half-apologetically. “The layoff certainly didn’t help,”

Donny McCrary managed to draw first blood, but not much else in his undercard bout against Yuri Foreman. Cut above the right eye midway through the first, the Belarus-born, Brooklyn-based middleweight shook off the wound to win a comfortable decision.

Just before the bell in the second Foreman rocked McCrary with a right hand that drove him backward several steps and onto his haunches, but the Missourian righted himself just short of going down. Then in the third, Foreman dropped McCrary with a left hook, which proved to be the fight’s only knockdown. Foreman remained in control throughout to win by lopsided scores of 100-89 (Pierre Benoist), 99-90 (Lynn Carter), and 98-91 (Eugenia Williams).

Foreman remains undefeated at 22-0, while McCrary is now 20-5-2.

In another prelim, New Jersey light-heavyweight Chuck (The Professor) Mussachio, 8-0, rolled over Tony Pope, scoring a third-round TKO over his overmatched Virginia opponent, now 15-13-1. After thoroughly tenderizing his opponent in the first round, The Professor scored a dubious knockdown in the second before dropping Pope with a right hand 53 seconds into the third. Referee David Fields intervened the moment Pope hit the canvas.

Two minutes into the second round, Ubaldo Olivencia missed with an overhand right and then turned, in obvious pain, away from opponent Jesus Rojas. Olivencia hadn’t even finished saying “Oh, F***!” when referee Earl Morton, recognizing that the Brooklyn fighter had dislocated his right shoulder, waved off the fight. The victory kept Rojas unbeaten at 5-0, while Olivencia’s record dropped to 5-10-2.

In a verdict that was not only unpopular with the crowd, but appeared to surprise both boxers, Newark welterweight Alex Perez (7-0) was awarded a unanimous decision in his four-rounder against Guyana-born Troylon Wilson (6-5-1). Benoist scored it 40-36, while Carter and Williams each had it 39-37.

In another early bout, New Jersey super-middleweight Wayne Johnson pitched a shutout, posting a 60-54 clean sweep on the cards of all three judges in handing Oklahoman Delray Raines his first defeat. Johnson is now 14-1, Raines 8-1.

DECEMBER 2, 2006

WELTERWEIGHTS: Miguel Cotto, 146, Caguas, Puerto Rico TKO’d Carlos Quintana, 147, Moca, Puerto Rico (5) (Wins vacant WBA title)

Antonio Margarito, 147, Tijuana, Mexico dec. Joshua Clottey, 147, Accra, Ghana (12) (Retains WBO title)

Alex Perez, 147, Newark, NJ dec. Troy Wilson, 147, Atlanta, Ga. (4)

LIGHT HEAVYWEIGHTS: Chuck Mussachio, 175, Wildwood, NJ TKO’d Tony Pope, 178, Norfolk, Va. (3)

SUPER MIDDLES: Wayne Johnsen, 164, Newark, NJ dec. Delray Raines, 164, Purcell, Okla. (6)

MIDDLEWEIGHTS: Yuri Foreman, 157, Gomel, Belarus dec. Donny McCrary, 157, St. Joseph, Mo. (10)

JUNIOR FEATHERWEIGHTS: Jesus Rojas, 121, Caguas, Puerto Rico TKO’d Ubaldo Olivencia, 122, Brooklyn, NY (2)