Marvin Hagler dispatched Wilford Scypion in the fourth round tonight, reducing the challenger to No. 48 on his knockout list. At 2:47 of the round, Scypion ran into a right hand thrown by the middleweight champion of the world, and the follow-up punches were unnecessary.

Hagler retained his title when referee Frank Cappuccino ruled that Scypion had not beaten the count of 10 on his attempt to regain his feet. Scypion's handlers led the benumbed challenger back to his corner like a traffic victim.

Actually, Scypion was having his best round of the fight when southpaw Hagler suddenly switched his stance and led with a left hand. It was while Scypion was engaged in blocking that shot that Hagler brought over a hard right to the head that started the challenger on the way down.

It was the first time Scypion had been knocked out in his 30-bout career.

"That's the way I wanted him, down at my feet," Hagler, 29, said after the fight. "He had a big mouth."

Before the fight, Hagler had said of Scypion, "I don't think his style will give me any trouble after one or two rounds."

Scypion, who had boasted he would go toe-to-toe with the champion, was the victim of that mistake. He scored frequently in the first three rounds with brave flurries but was taking hard knocks in return. Hagler led on the cards of all three judges.

The challenger's willingness to mix it up with Hagler was his definite undoing in the final round, which became methodical after Hagler stunned him with the telling right that set up the knockout, in Scypion's own corner.

The challenger was ahead in the scoring of the final round with continuous assaults until the big punch landed.

There had been surprise among the 15,000 in Providence's Civic Center when Scypion came out punching and actually bulled the muscular Hagler into the corners in the first two rounds, giving no ground in the wild swinging that ensued for long moments. However, Hagler confused the younger challenger with his ambivalence, his sudden transformations from left-hander to right-hander, a familiar Hagler pattern of combat. He was catching Scypion with both right and left leads.

After the fight, Hagler said, "I thought I had him in the first round." He did wobble Scypion with a surprise right hand, but by the end of the round it was Hagler who was covering up in a neutral corner after encountering a stiff left hook.

Hagler said he could sense Scypion tiring in the final round when he launched his final attack.

The challenger admitted after the fight that, "I froze. I didn't fight my fight." His trainer, Kenny Weldon, said it was not the kind of fight they planned, indicating that Scypion did too much head hunting.

Of the final series of blows, Scypion said, "I fell into it. I felt I was coming on in the fourth round and he caught me.

"I have no excuses. He's the champion."

That was obvious from the third round, when Hagler clearly felt he could control the fight. At the beginning of the round, he was boxing out of a right-handed stance, then quickly shifted back to the southpaw style. He landed several good head shots and also numerous solid right jabs in a row as Scypion kept floating forward.

In the fourth, Hagler landed a good right hook early, but Scypion kept coming. And at 1:15 of the round, Scypion landed two good head shots. Hagler answered with a sharp right-left a couple of seconds later and Scypion's left eye was swelling.

Then, as the round began to close, Scypion landed two good rights and, suddenly, it was over.

Hagler was guaranteed $1.25 million for his short work night, with the 24-year-old Scypion fighting for a $250,000 purse that was the biggest payday of his career.

The fight was sanctioned as a championship bout only by the newly formed United States Boxing Association-International. Because the fighters had allowed the USBA-I to appoint the fight officials, the World Boxing Association and World Boxing Council did not recognize the bout as a title match.

There was also disagreement because of the length of the fight. This one was scheduled to go 15 rounds, not the 12 that the WBC has instituted as the limit for its title fights.

But both organizations continue to recognize Hagler as champion and it is difficult to conceive that they would withdraw title recognition from him for fighting Scypion.

Earlier in the night, Hagler's next opponent was probably established when Juan Roldan won a unanamous 10-round decision over Irish Eddie Mann, a Philadelphia middleweight.

Roldan is ranked No. 1 in the WBA middleweight listing, and off his light-hitting performance tonight, seems to be an instant underdog against Hagler.

"They can't find anybody to compete against," said Hagler. "I'm thinking about retiring."

Hagler said he has talked about Thomas Hearns, Wilfred Benitez and Roberto Duran as opponents, adding, "I've challenged all these guys. Why should I wait for them?

"I'll want to take some time off and talk (retirement) over with my family."

But that retirement was not expected to take place for some time.