In a reversal of roles, Wilfred Benitez took the fight to famed aggressor Roberto Duran from the opening bell tonight and easily retained his World Boxing Council super welterweight championship before a sellout crowd of 4,500 at Caesars Palace.

Benitez abandoned his customary defensive boxing tactics, went out to meet Duran and used surprising right leads in almost every round to leave a flustered challenger wondering how to counter this new style.

Duran, who had boasted, "I will knock him out," was able to reach Benitez with solid punches only occasionally. He repeatedly was jolted by the champion's right leads and left hooks. There were no knockdowns. Duran suffered a cut over his right eye in the seventh round, but it proved no problem to his corner men.

Judge Dave Moretti scored the fight 144-141, judge Hal Miller scored it 143-142 and judge Lou Tabat had it 145-141. The Washington Post scorecard showed Benitez winning 10 rounds, with one even.

Benitez had weighed in at 152 1/4, Duran at 152 1/2.

"I was never hurt," Benitez said. "I thought Duran fought as well as he could, but I don't think I lost more than one or two rounds. I was just too smart for him. He hit me with only a couple of good punches all night. He's a smart fighter, but I'm elusive and I was in control all the way."

Benitez, often criticized for a seeming lack of interest in training and conditioning, said it was Duran who may have neglected some serious preparation for the fight.

"Duran has been one of the greatest fighters in history," Benitez said. "But if he hopes to continue fighting, he has to take better care of himself and train harder. Discipline is the most important factor in boxing."

Duran, who suffered his third loss in 77 pro fights, agreed he might not have been in top condition. He had indicated before the fight that he probably would retire if he lost, but after the bout, he said he was undecided.

"I don't know yet," Duran said when asked whether he would quit immediately. "I needed a little more training. He's very good, a good boxer. He ran a lot from me. My arms should have been a little stronger, though."

Benitez now is 43-1-1, the only loss coming when he was stopped by Sugar Ray Leonard with six seconds remaining in the 15th round of their bout for the WBC welterweight championship in 1979. Leonard said this week that he probably would give the winner of tonight's fight a shot at his consolidated welterweight title.

Duran made his strongest bid after the 10th round, winning the 11th, 12th and 13th, and his followers in the arena were screaming "Duran! Duran!" as the momentum changed. But in the 14th, Benitez rocked the challenger with a right lead and consistently got the better of Duran in later exchanges.

Duran was showing his famous grin of confidence as he took more control the fight after the midway point. But the challenger's supporters may have wondered what had happened in the early rounds, when Benitez was in full command, hitting Duran with left hooks and sudden rights that caught him by surprise.

It was a new strategy for Benitez, who is known as a counterpuncher. He was first off his stool, first to reach midring at the start of every round and first to throw punches. The champion took the fight away from the challenger, who was having trouble with Benitez's combinations of punches. He won nine of the first 10 rounds, leaving a knockout as the only hope for Duran.

The 12th round was Duran's best. He got to Benitez with two hard rights, and a third right in Benitez's corner shook him so badly that it appeared to be a turning point in the fight.

But at the start of the 14th, the champion hurt the Panamanian with another right lead.

Duran tried to strike back, but Benitez hit him again.

The 15th round was the fiercest. Duran moved Benitez into a neutral corner, and the fighters exchanged punches for more than a minute. Benitez appeared in no hurry to get off the ropes, and showed a willingness to slug it out on Duran's terms. Who won that exchange may be questionable, but at the final bell Benitez was still willing to fight, and retained his title.

In the main preliminary, Michael Dokes, the WBC's No. 2-ranked heavyweight contender, remained undefeated when he stopped Lynn Ball at 2:53 of the first round of a scheduled 12-round bout for the North American heavyweight championship.

Dokes, 24-0-1 with 13 knockouts, put Ball on the canvas twice with rights to the head. The second time, Ball struggled to his feet but was wobbling, and referee Davey Pearl stopped the bout.

Ball is 18-5.

In an earlier fight, unbeaten Edwin Rosario of Puerto Rico, the WBC's No. 2-ranked super featherweight, scored his 23rd victory and 22nd knockout, beating Ezzard Charles of Houston. Rosario hit Charles repeatedly in the head and put him down for the count at 2:07 of the third round.

In a 10-round middleweight bout, Mark Holmes of Easton, Pa., the unbeaten younger brother of WBC heavyweight champion Larry Holmes, jabbed his way to a unanimous decision over Ted (TNT) Sanders of Los Angeles. Holmes is 18-0 and Sanders is 8-14-4.