After watching middleweight champion Marvin Hagler beat Fulgencio Obelmejias with a fifth-round knockout early this morning in their championship fight, welterweight champion Sugar Ray Leonard, who was on hand to serve as a television commentator for the fight, said he would be no match for Hagler.

"He proved to be one of the best middleweights in boxing history and his fight with 'Obel' convinced me I am too light and small to fight him," said Leonard.

There had been a published report that Leonard, who underwent surgery to repair a partially detached retina in his left eye May 9, would return to the ring and fight Hagler next summer at Baltimore's Memorial Stadium. But that report was discounted as simply speculation preceding Leonard's scheduled Nov. 9 announcement about his future.

Meanwhile, Obelmejias claimed he lost the fight because Hagler jabbed a thumb in his right eye in the third round. Hagler's response: "He's crazy."

"Halfway through the third round, Hagler jabbed his thumb in my right eye and from that moment on I was blind. I couldn't see anything," the Venezuelan challenger said after Hagler knocked him out in the fifth round early this morning.

"I was beaten by a great champion, but without that thumb-jab things could have been different," Obelmejias said.

A television replay showed that the hook that finished Obelmejias, after a wild two-hand combination, was a right that landed on the challenger's jaw. Originally, it was thought a left was the knockout blow.

Obelmejias, 29, has suffered the only two defeats of his 40-fight pro career in title fights against Hagler. Hagler's victory was his 55th in 59 fights; he has 47 knockouts.

Hagler was thinking about his future after the fight. It doesn't include a rematch with Obelmejias, he indicated.

"Obelmejias is nothing," Hagler said. "Much stronger than him are Tony Sibson and (Frank) "Animal" Fletcher and I'll meet them both next year, first the Englishman and then the American."

Pat Petronelli, one of Hagler's managers, confirmed contacts were under way for Hagler to meet Sibson, who is Britain's No. 1 challenger, in Monte Carlo in the spring.