Thomas Hearns sat on the console television in his suite at Caesars Palace and pushed up the sleeves of his flaming-red Gucci sweatshirt. Then he picked at the Italian crest on the hip of his flaming-red Gucci sweatpants. Had the "Hit Man" ever looked or felt better?

The greasy mass of curls he wore only a year ago was gone, his hair clipped smooth and close to the scalp. He had removed the undisciplined colony of whiskers that had run across his jaw and had fashioned a body of facial hair not unlike a goatee. Take away his leather slippers, which were cracked in spots like the pocket of an unoiled catcher's mitt, and Hearns looked like the sort of fellow you might find loitering about the steam room in an ultra-fern health club.

Once a Detroit tough, a street kid with big fists and a nice clean dance step, Tommy Hearns is now rich and comfortable and 27. He made millions fighting Marvelous Marvin Hagler last April in one of the most violent and spectacular confrontations in recent boxing history. Hearns dropped to the canvas in the third round and lay flat as a sheet of drywall, gazing past the screaming wash of ring lights at the blackened ceiling of the world.

Monday night, he and Hagler will again do battle in the outdoor arena at this desert resort, only this time with different opponents. Hearns challenges James Shuler for the North American Boxing Federation middleweight title, and Hagler defends his undisputed middleweight crown against John Mugabi.

"This is it for me, my last year," said Hearns, the current World Boxing Council super welterweight champion and the former World Boxing Association welterweight king. "I want to be the first man ever to win four titles, and I want to win the other two this next year so I can walk away from boxing."

Hearns probably will face Hagler in a rematch on June 23 if both fighters win Monday night. But some, particularly Shuler and his distinguished trainer, Eddie Futch, predict an upset.

"There's got to be some residue in Tommy's mind from the devastating loss to Hagler," Futch said. "There's just got to be. The last time he was in the ring, he ended up on his back. He's got to be wondering if that could ever happen again. No matter what the public's perception of the fight may be, James will beat Tommy because James is a better fighter at this time than Tommy is."

Shuler said he thinks Hearns has conquered what bad memories he may have of the Hagler fight and is in possession of what he calls "a mind very well put together." To his credit, Hearns has laughed and talked openly about the beating he suffered.

"By the third round," he said, "I'd already broken my right hand and my legs were spent. I was thinking, 'You've given it all you've got and the man keeps coming. What do you do now, Thomas Hearns? You run.'

"That hit my mind, to run. But my legs talked to me and said, 'Nope. You can't do it. Tommy, you're all alone. You can't go anywhere.' "

Although he said he was not proud of his performance against Hagler, Hearns claimed not to feel "totally, totally bad about it." He said he threw his best stuff and landed blows that would have made other fighters "wiggle and dance for you. But with a man like Hagler, you could hit him with a baseball bat and he'd keep coming. You want to drop that bat and go, because there he is, taking everything, starting it all over again. Then the legs, both of them, were talking at the same time. They're both exhausted. When they check out, they check out together."

Hearns hopes to look sharp and hungry against Shuler and regenerate the respect of a boxing public that has come to view him as a gifted fighter unable to win his most important bouts. At 40-2, Hearns' only other loss came against Sugar Ray Leonard on Sept. 16, 1981. If Hearns is less than impressive against Shuler, and Hagler whips Mugabi, the selling of a Hearns-Hagler rematch may be a difficult chore for Top Rank, Inc., the promoter of Monday's card.

"How I look is so important," Hearns said. "I have to go out and show everybody why I can beat Hagler if I fought him again. I must put on a great show against James Shuler. It's not on Marvin; it's on me.

"When you lose, it's important to come back and win again, right away. It shows you can't keep a good man down. I myself like to hear all the people who doubt me and say I'm finished. I like to see their faces when I prove them all wrong. Then they say he's not all washed up, he can still be champ."

Since losing to Hagler, Hearns said meeting unkind strangers on the street can sometimes send him reeling, especially when they remind him of his failure to take the middleweight title from the bald-headed man who has held it for almost six years.

Said Hearns, "You hear words from people who make you want to tell them to shut up or put up. I guess you have to learn to hear and not to hear. If I let all that business get to me, I'd be locked up today . . . To all those who say ugly things, all they're doing is loading up for a whooping. And I'm the one who'll do the whooping."

Hearns then described himself as a light switch, being able to turn his rage and fury on and off once he steps into the ring. "Anybody who knows me knows I can be a total animal," he said, sitting on the television set in his Italian sweats, rich and comfortable and 27.