Wilfred Benitez, the champion, hasn't talked to reporters for three days. "That is my policy," he said. Four days before every fight he takes vows of silence concerning the boxing press. The writers don't argue because they know Benitez sometimes is, well, peculiar.

Even his manager has described Benitez's behavior as somewhat strange. "Just before his title fight last year with Maurice Hope, Wilfred suddenly broke training, stole off and took a three-day vacation, to my amazement," Jim Jacobs said. "I agree he is unreliable sometimes, but I still think he's the greatest fighter in the world."

Benitez, who agrees he is the greatest, is defending his World Boxing Council super welterweight title tonight in the Caesars Palace sports pavilion against Roberto Duran, a chatterboxer who talks to everybody. Of himself and Benitez, Duran says to all and sundry, "I will knock him out."

The championship bout, which is expected to start about 10 p.m. EST, will be on Home Box Office cable television, and a closed circuit telecast will be shown at the Warner Theatre in Washington. Tickets there are $15 each. The cable telecast begins at 9 p.m., the Warner Theatre telecast at 8:30.

In Las Vegas' bookmaking shops, Benitez is an 8-5 favorite. But there has been a steady loss of confidence. Three weeks ago, the odds against Duran were 3-1, later dwindling to 11-5.

The contest is advertised as the super welterweight championship of the world, but it seems more like a 15-round confrontation between Panama and Puerto Rico. The hundreds of followers of Duran and Benitez--who was born in the Bronx of Puerto Rican parents--form two opposing camps. Benitez's manager says, "It's not so much the title that is motivating Wilfred. He knows about Duran as a legend, and now Wilfred wants the glory and the recognition as the greatest Latin fighter."

Duran has much ground to make up. He is committed to redeeming himself in his own land. Once the unrivaled hero of his country, Duran has been booed there by embittered Panamanians because he walked away from a losing November 1980 bout with Sugar Ray Leonard in the eighth round, surrendering his welterweight title on a technical knockout. "Roberto feels he can't go home again unless he wins Benitez's title," said Ray Arcel, his trainer.

What is coming up Saturday night is a fight pitting the skinny technician, Benitez, against the chunky, aggressive Duran, a postgraduate street fighter. Rarely have two fighters with such different styles met for a title. With customary arrogance, Benitez says, "I am the Bible of boxing," and indeed his polished defensive skills may be unmatched.

Benitez finished his training yesterday by delivering karate kicks against the light bag that was swinging overhead, then looking toward the spectators for compliments. With his thin, penciled mustache and ready sneer, he looks like a villain.

The only man able to defeat Benitez--who has fought 44 times since turning pro at the age of 15 and won his first title at 17--was Sugar Ray Leonard. That fight was stopped by the referee with only six seconds left in the 15th round to rescue a badly pummeled Benitez. But never had Leonard missed as many punches as he did that night. "Benitez is a ghost," Leonard said. "He anticipates your moves and almost makes himself invisible. I had to wear him down. I never met a better defensive fighter."

But Benitez isn't merely a defensive boxer. He has knocked out 26 of the 44 men he has fought, indicating he can bring up a punch from somewhere. His manager says Benitez did not train well for the Leonard fight because "I couldn't get Wilfred to take him seriously."

When Benitez went for the super middleweight title last May, he brought it off with a 12th-round knockout of Hope. When Benitez was told after the fight that he had knocked out two of Hope's teeth, he seemed unconcerned.

He said in Spanish, "Puedes poner tus dientes debajo de la almohada"--"He can put his teeth under his pillow."

Sugar Ray Leonard will be here for the fight as color commentator for Home Box Office. "I'll have a good ringside seat to study the two guys I might fight again," Leonard said from Phoenix, where he is now in training.

"They'll be throwing punches at each other, but they'll really be aiming at me," Leonard said. "They'll know where the pot (money) is. I'll probably accommodate the winner."

Leonard is one of the two fighters to defeat Duran, and the only one to knock him out. At 30, Duran is seven years older than Benitez, and since his debacle against Leonard has won two fights in his comeback attempt. But Duran hasn't stopped anybody in his last four fights, and he himself was stopped in one of them.

"Roberto will be more comfortable at 154 pounds than he was at 147 against Leonard," Arcel said. Weight has always been his problem. A week after he weighs in at 147 he balloons to 170. He has an obsession with food that probably dates from his boyhood, when he had to fight for something to eat.

This time, Arcel said, Duran has been a Spartan in training. "He's been working out next to a prison in Panama, and there has been no nonsense. He is the best conditioned Roberto Duran I ever saw."

Angelo Dundee, Leonard's trainer, says the fight is a difficult one to call. "They're both so emotional, it could break out in punches at the weigh-in," Dundee said. "I have not seen the likes of the Latin temperaments of those two. Duran wants it bad, he had been such a hero in Panama. Benitez can throw punches from any angle. How will he do against Duran? It all depends on which side of the bed Wilfred gets out of the morning of the fight." Others speculate that Duran will go after Benitez as aggressively as he can the first two rounds, and if that doesn't work, he could get discouraged.

They'll both be well paid. For his night's work, Benitez will get $1.1 million. Duran will get about $700,000, which, like the millions he earned previously, will be invested by his Panamanian banker.

One big winner is Jacobs, the former national handball champion and owner of the best collection of films of famous prizefights, including some from the turn of the century. In a gamble that can be admired in Las Vegas, Jacobs three years ago bought the moody Benitez's contract from the fighter's father for $75,000. Jacobs will get a $335,000 payday tomorrow night--one-third of Benitez's latest purse.