As he sat on the canvas in the 10th round with bloodied eyes and a brain full of pain, Alexis Arguello was somehow able to make a decision few fighters make on time. He de-cided to stay where he was. He decided it was over.

"I was hurt," Arguello said tonight after his un-successful attempt to take Aaron Pryor's WBA junior welterweight title. "I didn't want to risk my life. I said to myself, 'That's it.' "

Referee Richard Steele hovered over Arguello, who had bounced up from knockdowns in the first and fourth rounds, and waited for him to rise. But at 1:48 of the 10th, Arguello was in no shape for further punishment, a dish that Pryor would sure-ly have served.

"He didn't say a thing to me verbally," Steele said. "But he knew he was beaten. I looked at him, he looked at me, and I counted to 10."

Pryor, 27, is undefeated in 34 fights, having knocked out 32 of his opponents. His knockout percentage is the highest in boxing and most con-sider him and Marvelous Marvin Hagler the finest boxers active.

Pryor scored constantly against Arguello with clubbing overhand rights and, later in the fight, straight lefts. It was a stiff left that backed Ar-guello against the ropes and set up the final bar-rage that put him down.

"We both went out with everything we had," Pryor said. "He was more confident than he was in our last fight."

Both men announced plans to retire, but only Arguello, 31, the veteran of 84 professional fights, is expected to keep his promise. Pryor is vying for a lucrative match with Ray (Boom Boom) Mancini.

After the fight, Arguello wept without shame. An aide in his camp offered him the traditional sunglasses, intended to shield all emotional and physical bruises after a fight, but Arguello waved them away and accepted applause from all those around him.

"My heart was there, my condi-tion was there, my blood was there, but he was too strong," he said.

Arguello wanted badly to become the first boxer ever to hold four ti-tles. He has held featherweight, jun-ior lightweight and lightweight championships. Only six other fight-ers--Bob Fitzsimmons, Henry Arm-strong, Barney Ross, Tony Can-zoneri, Wilfred Benitez and Roberto Duran--have held as many.

"I wanted to do something differ-ent," Arguello said.

But as in their first fight last Nov. 12 in Miami's Orange Bowl, Pryor was a relentless puncher, gaining strength, it seemed, every time his opponent scored. Although Arguello scored well with the judges in the sec-ond, third and eighth rounds, Pryor was only hurt a couple of times.

Through nine rounds, judges Chuck Minker and James Rondeu had Pryor leading and James Jen Kim scored it even.

In the first fight, a brutal 14-round technical knockout that most considered the best fight of 1982, Arguello went toe to toe with Pryor and the challenger made the same decision tonight. As if it were phys-ically possible, both men pursued each other, neither willing to back away from the other. Pryor opened the fight with a vicious right that dropped Arguello, but the challenger rose quickly.

"When he called us out to the middle of the ring, I felt really clear," Arguello said.

Arguello scored well enough in the second and third with left hooks and jabs to win the rounds.

In the fourth, Pryor smiled through Arguello's punches and stalked him. Again, a right rocked Arguello and put him down. Again, he got up.

"He got up with his heart," Pryor said later.

The pace slacked some in the fol-lowing rounds, but only a little, as Pryor kept coming at Arguello, working his left jab and following with the overhand right.

"I don't think there's anyone like him, he's so strong, so strong," Ar-guello said.

Emmanuel Steward, who became Pryor's trainer after Panama Lewis was banned from boxing for illegal practices by the New York State Athletic Commission, said his fighter changed his strategy slightly in the last couple of rounds, a change that may have led to the knockout.

"I felt that we were losing the fight at an (early) point," Steward said. "At the end of the ninth round we saw that we were hitting him with rights, but (Arguello) was mov-ing his head away. So we went to straight lefts between the gloves."

The straight left and then the combinations that put Arguello on the ring floor for the last time in the fight and his career were reminiscent of the brutal 14th round in Miami last year.

"Alexis wanted to go out a four-time champion, I wanted to go home with my title," Pryor said. "It was do or die for both of us. I never knew when I would go home."

In a preliminary bout, Rocky Lockridge fought a masterful fight to upset former junior lightweight champion Cornelius Boza-Edwards in a unanimous 10-round decision.

Lockridge, 26, may now challenge WBA junior welterweight champion Roger Mayweather. Lockridge out-smarted and outpunched Boza-Ed-wards after suffering a first-round knockdown.