Sugar Ray Leonard said yesterday that Marvelous Marvin Hagler's recent title defenses had taken their toll on the middleweight champion, and that his own long layoff from the ring would be no handicap if Hagler accepted his challenge to fight.

"He's been fighting, I've been resting," said Leonard, going against conventional boxing wisdom that says a fighter who has been active has a clear advantage over one who hasn't been.

Leonard said Hagler had experienced especially tough bouts with Roberto Duran, Thomas Hearns and John Mugabi. "They do take their toll," Leonard said.

"He throws less and less combinations now," Leonard said, "not like the Hagler of two, three years ago."

In a meeting with editors and reporters of The Washington Post, Leonard also said that he had the strategy to beat Hagler, and that he would not give Hagler a rematch if he beat him -- that his challenge to Hagler was a "one-time thing."

Leonard said that he would like to fight Hagler in September, but that he and his adviser, Michael Trainer, "have not heard anything concrete."

Although Hagler has been "somewhat of a hermit," according to Leonard, since Leonard's May 1 challenge, Hagler has said he will hold a news conference in June to name his next opponent -- either Leonard or Hearns, who was a third-round victim of Hagler's in April 1985. "He wants me and Hearns there and then he'll let us know what's going on, but I won't give him that satisfaction," Leonard said.

Leonard said he believed Hagler wanted to fight him just as much as he wanted to fight Hagler. In fact, Hagler's manager, Pat Petronelli, said May 8: "Every guy in the street knows who Marvin would like to meet first -- Leonard. He fought Hearns before. The only challenge for him is Leonard."

On NBC's "Tonight Show" recently, Hagler said, "I'm going to sit back and lick my chops and just wait." Leonard interprets Hagler's delay as a necessary ploy so it will not appear that Leonard can call the shots with Hagler, even from retirement. Still, Leonard said yesterday the wait had caused him some doubts. "Sometimes I think in June -- I hope I'm wrong -- that he will have his press conference and say, 'I've decided to fight No. 1, Thomas Hearns, and, Ray, you wait.' "

But in response to questions that his layoff will hurt him, Leonard countered with an opinion that Hagler's schedule has been taxing. Granting that Hagler is "just as awesome as ever" and that he "fights like he's fighting for his last meal," Leonard said Hagler had to feel the effects of being "beaten up by the Mugabis of the world."

Hagler and Mugabi, said Leonard, "exchanged ferocious punches. Hearns was only three rounds, but it was a brutal three rounds. It was so fierce it was unreal.

"He had a tough 15 rounds with Duran. It takes its toll."

After Hagler (62-2-2) beat Mugabi with an 11th-round knockout in March, a fight in which Hagler's right eye was swollen almost shut, Goody Petronelli, Hagler's trainer, said the Mugabi fight was one of the three toughest defenses Hagler had had since he won the title in 1980. The others were against Hearns in 1985 and Juan Roldan in 1984.

Hagler, who turned 32 yesterday, has defended his title 12 times -- only two short of Carlos Monzon's middleweight record of title defenses -- and Hagler has earned the reputation of fighting the best available man. On the other hand, he has been spacing his fights more in recent years, and four of his last five bouts could be considered extremely rugged: November 1983, when he went the 15 rounds to win a decision from Duran; March 1984, when it took him 10 rounds to knock out Roldan; April 1985, against Hearns; and March, against Mugabi. Only in October 1984 did he have a relatively easy time, when he knocked out Mustafa Hamsho in three.

Leonard made it clear that he hoped not to trade punches with Hagler, as Hearns did.

"I look at Hagler. I see his ability. I see his determination. But I don't have to beat the guy physically. I can beat him mentally.

"I feel I can frustrate Hagler. Hit there, hit there. Couple times there. Frustrate him till he starts telegraphing his punches, which is something I've seen."

Leonard said he did not know which way Hagler would fight him -- "run at me the way he raced over to Hearns," believing that Leonard's layoff will hurt him, or lay back "in respect." Leonard said the only time he had seen Hagler lack aggressiveness was against Duran. "He stayed back more, mainly because of Duran's experience."

Leonard said that he appreciated the concern of people who fear that he will be hurt if he comes back to the ring, but that "I know what I'm doing." He said that the partially detached retina of his left eye suffered in 1982 was no problem, that he had been cleared by doctors. Unlike some fighters who have suffered permanent physical damage in comebacks, Leonard said that he was still young (30) and that he would fight only once.

Leonard said he had wanted to fight Hagler since he beat Kevin Howard in May 1984 and then retired for a second time -- that the lack of a bout with Hagler had been a "void" in his life. When he and his wife and Hagler and his wife dined together several months ago, he said Hagler told him, " 'Sugar, darling' -- and that irritates me, too -- 'it could have been a great fight.' We just kept saying it'd have been great."

Now that he wants to fight, he said he believed Hagler would concur in the "one-time only" proposal. "We will both agree," he said.