AT 23, Sugar Ray Leonard is full of confidence. Whether he is in Palmer Park or in New York City, Montreal or Las Vegas, he balks at nothing.

But he is beginning to feel the pressure of his upcoming fight in Montreal.

His stomach juices churn. He despairs of total acceptance. He has finally opted to put his trust in children, who lack ulterior design, much as did a disillusioned Sonny Liston.

"I won't be nervous the day of the fight," he says of his onrushing reckoning with Roberto Duran, the baby bull from Panama who once scowled at a horse and then slugged the uncomprehending animal.

"I have no fear," Leonard says, but with less than a month to go before the June 20 bout he says of the immensity of the promotion: "Sometimes I get to thinking about it and I get a little catch, cramped, a little tightening of the muscle."

He cautions that there is no relation to any doubt in his mind about his capability. "I have never doubted myself, though thoughts have crossed my mind. I know what I can do. I look in the mirror and I say, 'You can do it, get to it.'

"Before I fought Wilfred Benitez for the title, I was intimidated by all the pressures surrounding the bout, but in my first degree, against David Green, I was perfectly relaxed, as if it were a preliminary bout. I'll be relaxed for Duran. He's going to get a big suprise."

Leonard says he needed the security of training in the Oakcrest Recreation Center in Capitol Heights. "I'm relaxed," he explains, "after all that static of deciding when the bout with Duran would be, where, and for how much. All that jive has been resolved."

Can he prepare properly with the quality of sparring partners available, in contrast to workhorse Duran, who has the pick of high-caliber foils in New York as he adapts his pace to Latin-American "salsa (hot sauce)" music?

"i've got four dynamic sparring partners. They're durable and very strong.

Each has one quality. One keeps coming at me. Another has a big punch. One is powerful. One is very temperamental. The four of them together make up another Duran."

Leonard chuckled roguishly at his reference, suggesting that Duran can be "psyched" into losing his cool in Montreal.

When the bout was first agreed upon, Ray Arcel, Duran's trainer, remarked somewhat gratuitously: "Roberto is a great kid besides being the best fighter in the world. He knows who his friends are. He's loyal to them, and supportive of them. He would never have permitted anyone to knock me down, the way that guy did to Angelo Dundee after Leonard's bout against Green."

Asked to comment last week. Leonard said, "It's not my duty to be a bodyguard; it's their (his handlers) job to protect me."

Despite having laid of for six valuable days because of a freak injury in training, Leonard does not begin his workouts until nearly 6 p.m. "I like to work in the evening, when the kids work out. I get motivated from them. I'm self-motivated, but their admiration gives me a lift and every little bit helps."

Montreal revisited will be an occasion for a sense of patriotism reinforced, at the stadium where he won a gold medal in the 1976 Olympics.

"I really feel Duran will bring Panamanians with him, and, look, I'm from D.C.-Maryland area. I will represent the United States like I did in the Olympics. I'll have the same spirit. It all helps a little."

Some of Leonard's psychological tactics can be traced to the respect he gained for a fighter like Marcos Geraldo and from the craftiness of Benitez. g

"I knew Geraldo would give Marvin Hagler a problem on Saturday (Hagler had to settle for a 10-round decision)," Leonard said. "I knew Geraldo was as good as any middleweight. He knocked the hell out of me (as a welterweight). He's a puncher who gave me double vision for a while. He's tall, aggressive, he'd good. But people wouldn't believe me. They'll always doubt me."

Was he implying that even a victory over Duran will not be a door to final acceptance of his (Leonard's) greatness?

"They'll say Duran is getting old (29), but I'm not proud; I admit I hope his age is bothering him on June 20. That's what makes me outstanding; if my opponent has mostly speed, or intelligence, or punch, I can dominate him."

A model of attention to conditioning, Leonard acknowledges he finds training almost as difficult to face up to as Muhammed Ali does.

"I laid off for three months after the bout with Benitez," he said. "Every bone ached the first day back for Green; my muscles were soft, I didn't want to train. It's tough now after just a week off. But if you're in the right frame of mind, and not injured, it's okay, I hid the ankle I injured playing basketball at two press conferences.

"But my arm is okay," he said of the cut he suffered last week, nevertheless leaving some doubt by taking a week off.

"It wasn't the way it came out. It wasn't a light bulb I broke while skipping rope. A fluorescent tube exploded. My father was standing near the ring in the gym. He was in a state of shock, with the noise and the blood.

"I knew what happened when I heard the noise.My first instinct was to move. I feared for my eyes. The falling glass sliced the inside of my upraised upper right arm. It wasn't bad; I got stitches just to minimize the scar."

If he is "hiding" the extent of that injury, too, will the arm be fit to be raised in victory on June 20?

"What do you think?"