Marvelous Marvin Hagler, proving once again that he is the best middleweight in the world, now will set his sights on Frank (The Animal) Fletcher and Juan Roldan later ths year.

Tony Sibson, proving that he has a lot to learn, will return to England and attempt to work his way back to another championship fight.

Hagler defended his world middleweight title for the sixth time Friday night, pounding Sibson's face into a bloody mess and knocking down the No. 1 contender twice before earning a sixth round TKO. Afterward, Hagler proclaimed himself "the greatest middleweight champion of all time."

He'll face Fletcher, who will probably replace Sibson as the World Boxing Council's No. 1 contender, on May 20 or 21 in Atlantic City. Then would come Roldan, the Argentine fighter rated No. 1 by the World Boxing Association. That fight probably would take place this summer in Hagler's hometown of Brockton, Mass.

"I'm going to be busy for the rest of February doing personal appearances," Hagler said Saturday. "Then I guess it'll be the Animal--if he wins Sunday."

Fletcher was scheduled to face Wilford Scypion in Atlantic City.

"Then I guess we'll try for Roldan," Hagler continued. "My people are talking it over and whatever they decide, I'll do. I feel I'm the best middleweight in the world and I want to prove it."

Hagler proved it Friday night before a crowd of 13,577 that packed the Centrum despite a snowstorm.

He raised a lump on Sibson's left eye in the first round and had blood pouring from his nose in the fourth. Hagler sliced open the eye early in the fifth round and he decked Sibson twice in the sixth before Referee Carlos Padilla stopped it.

"I lost to a great champion and now I know what it takes to become champion," said Sibson, who wore dark glasses today to cover the 16 stitches around his eyes.

"I feel more frustrated than anything. I worked really hard and I'm frustrated that I didn't do better. I have no aches and pains--just a busted eye. I've never been cut before, even back to when I was 10 years old. Nobody has ever done to me what Marvin Hagler did last night."

Hagler made $1.6 million from the fight, which was telecast by Home Box Office and on limited closed circuit in the United States and England.

Hagler, 28, is 56-2-2 with 47 knockouts. Six of those knockouts have come in six title defenses.