The great ones do it when it can't be done. Ray Leonard did it, scoring a technical knockout at 1:45 of the 14th round for the undisputed welterweight championship, when Thomas Hearns had turned his pretty face ugly.

After Hearns was born again in the middle rounds, a cobra delivered from a mongoose's deadly strike, he danced about in the 13th round with every good reason to say this night was his. Two minutes later, in the 14th, Leonard was the winner on a night when all three judges had Hearns ahead on points.

It didn't end in the 13th, a round memorable for Leonard's relentless attack built on reserves of energy long thought lost. In those two minutes, though, Leonard destroyed the iron will of the kid from Detroit whose torso so flares with muscle that flacks call him "The Motor City Cobra."

The operative image of that decisive round is Leonard, at 5 foot 10, doubled in a crouch with his head pressed up against Hearns' breastplate. Hearns was helpless, a taller man ready to be lifted off the floor and put to bed. From his crouch, Leonard pumped a dozen punches, maybe more, up at Hearns' head.

The concussions finally tilted Hearns off his statue's base, and he went twisting, reeling sideways. Always the faster man with his hands, faster afoot, too, Leonard did his mongoose work, chasing the cobra in circles until finding a vulnerable spot. A left hook sweeping in from California caused Hearns to stumble against the ropes.

They called Joe Louis the best "finisher" ever because he never started a man to insensibility without quickly finishing the job. Leonard is such a violent tactician, suddenly more accurate with his punches, quicker with them, all directed at the victim's head.

Hearns fell through the ring ropes, not far from his own cornermen, and was sprawled there, jackknifed over the second strand. The referee, Davey Pearl, ruled no knockdown, saying it was a fall. With a minute left in the 13th, here came the game's best finisher looking for a way to end it.

The eyes saw it, but the brain lost count of the punches. The memory is of Hearns not falling to the canvas, but simply coming down like a building brought down by carefully placed explosives. Coming down, Hearns' hindquarters snagged on the second rope, and there he sat, his eyes unfocused, as the bell ended the 13th round.

As astonishing as Hearns' midfight comeback had been -- Leonard seemed ready to end it in the sixth, but four rounds later Hearns again was the predator of the early fight -- it was no more a miracle than his survival of that 13th round.

A minute's merciful respite on the stool was not enough to deliver Hearns' motor skills back to him, especially against a finisher with a job to finish. Leonard virtually ran across the ring to begin the 14th round, perhaps aware that he was losing on all three scorecards, certainly aware of the long and loud advice from his cornerman, Angelo Dundee, who for three rounds had shouted, "Come get him, come after him."

Now for the 14th, Leonard's confidante and trainer, Janks Morton, stood at the corner and waved frantically, telling Leonard it was time to stay in Hearns' face. In the early rounds, Leonard was an Ali dancer who seemed content to avoid the danger of the cobra's quick-striking right hand. By the margin of those rounds, Leonard was losing as the 14th began.

It was soon finished.

Finished in Louis style.

Hearns didn't even go down in the 14th, but Leonard was so clearly capable of hurting him that referee Davey Pearl stopped the fight as Hearns again sagged into the ropes.

There was no argument from Hearns or his trainer, Emanuel Steward.

The only argument worth pursuing was the officials' scoring. The three men had Hearns ahead by two, three and four points. Had Leonard won the last two rounds in routine fashion, he would have lost a split decision. The argument here is that these officials missed a nice fight, for nearly every unofficial card at ringside had Leonard a clear winner.

The sixth and seventh rounds were enough to prove it. After the early defensive dancing by Leonard gave Hearns a head start, Leonard turned aggressor in the sixth. A left hook to the ear staggered Hearns, another to the kidney doubled him over.

Again in the seventh, Leonard dominated Hearns, at one point raining in six unanswered punches.

Somehow, Hearns survived. For the first time ever, though, he was forced to retreat. His defensive withdrawal, covered by a jab flicking at Leonard's face from afar, lasted for four rounds until he returned to his instinctive style, that of the big banger looking for the 31st knockout of his 33-fight career.

Now, there could be no question of Leonard's design. His left eye was closing. He was behind on all scorecards. Hearns was on the prowl, even seeming cocky. Now was the time to be great.

This week Leonard said, "I've already made a dent, and now I want to make a hole . . . It's neat that I'm two separate people, the personality and the fighter. But I want to keep people's memories of Ray Leonard, the fighter, vivid. Don't forget me in the ring."

No one will now. In less than two calendar years, Ray Leonard has knocked out four champions, three of them undefeated at the time: Wilfred Benitez, Ayub Kalule and Hearns. The other was Roberto Duran, who saw the greatness coming to Leonard and walked away before it hurt him.