Sugar Ray Leonard was working magic yesterday at Capital Centre but had the devil's own time trying catch up with David Green.

The welterweight champion already has attracted an advance sale of $100,000 for his bout on Monday night at the Centre against the Englishman. Leonard found the chin of a sparring partner yesterday with an uppercut that toppled him to one knee. Leonard peppered his nose with so many jabs that the fellow showed up at ringside later holding an ice bag to the tender area.

Leonard lingered at the arena in sweaty work clothes, hoping for a confrontation with Green. He referred to the Englishman as a "face fighter" for the benefit of any undercover man who might be inclined to relay the insult to Green. "He leads with his face first," Leonard said, "and then throws punches from all angles. I like that."

Leonard even said, "I hope all the judges are British so Green won't have any excuse."

Green's camp sent word to the Centre that he wouldn't come there until Leonard had left and did not want Leonard to see him work out.

Leonard kept asking, "Is Green here yet?" as if he were determined to flout the Englishman's wishes and "psych" him, a la Muhammad Ali.

"Is there anything I can say to make Green mad?" Leonard asked his interviewers. "It might work; it might make the fight easier."

When Green did arrive, he was asked why he was so intent on avoiding a confrontation.

"I met him once," Green said of their encounter here at a news conference announcing the bout. "I don't want to get to meeting him so much that I will like the fellow, now do I?"

At that time Green brought with him a television tape of his losing fight against former champion Carlos Palomino, but showed only one round of it here.

The question of about Green's worthiness as a challenger increased when he went to Knoxville, Tenn., to box, in the camp of hometown favorite John Tate.

Green was persuaded to come here yesterday to stir interested in Monday's show because Leonard is trying to sell out Capital Centre to avoid blacking out the telecast of the fight locally.

In fact, fans at Capital Centre will see telecasts of the Tate-Mike Weaver bout from Knoxville and the Larry Holmes-Leroy Johnson bout from Las Vegas on the Telscreen.

Green finally put the gloves on with sparring partner Des Morrison, who beat Green to the punch with jabs and with fast right hands during three minutes of action and suddenly it was all over after the one round.

They took off the gloves before anyone really got a line on the Englishman's style. Smith, insisted, "We did not come here with the intention of sparring at all. We did the one round just for the television cameras. Davey got up at 3 a.m. to come here."

Green was in the midst of mere shadow boxing when Leonard appeared in street clothes, accompanied by Manager Angelo Dundee, who shouted at Green, "Don't show too much; here comes the enemy. Don't throw your best shot."

In answer, Green twisted his facial features into a snarl as he struck out vehemently at his shadow. There was no remark from Leonard, who drifted away.

Green, interviewed at ringside, was asked about Leonard's remark about being a "face fighter," one who catches a lot of punches because of a lack of defensive skill.

"Do I look a face fighter?" Green demanded. "We'll see on March 31st."

Was there anything Leonard could say that would make him mad?

"No."

Did he still think he could win, as he said on his visit here for the contract signing?

"I'm going to win," he said. "It's not 'can I win.'"