PARIS, OCT. 18 -- World champion Michael Nunn invited Donald Curry to show he had the punching power of a middleweight.

Curry failed. Nunn proved his point, and kept his title tonight.

Curry, formerly a welterweight and light-middleweight champion, hit the target often, but didn't have the power to worry Nunn, who always has been a middleweight.

"He never hurt me, but he gave me good shots," Nunn said after his 10th-round knockout. "I was testing his strength, seeing how strong he was. He was moving up and he deserved the opportunity to try and he got it and I beat up on him.

"I was just too big for him. He fought his way to number one and naturally with him moving up I was bigger and stronger."

Nunn, 27, overpowered Curry, 29, with 15 unanswered punches in the 10th round that floored the challenger and referee Denny Nelson ended the fight. The champion held on to his International Boxing Federation title and remained undefeated in 36 fights.

Nunn cut Curry (33-4-0) in the second round, floored him in the seventh and generally had too much power.

Some 13,800 fans roared their approval of Nunn's performance, in which he showed a variety of punching skills, fancy footwork and touches of humor.

Outreached by five inches and two inches shorter than the 6-foot-1 champion, Curry tried working low in the opening round.

But Nunn, advised now by Angelo Dundee, had all the tricks. He smiled at Aktar Muhammad, Curry's business adviser, who taunted him with shouts of "Run, Michael, run."

He rolled his stomach muscles in true bodybuilder fashion when Curry caught him on the ropes and Nunn even tried to help the challenger to his feet when Curry slipped in Round 2.

In the seventh, Nunn chased Curry into a corner and a cluster of punches dropped the challenger to his knees. He was up at three and continued to push forward. But, by the ninth round, Curry was tiring fast.

Now it was Nunn's turn to go forward and he repeatedly landed long right jabs and follow-up lefts to the face.

In the 10th, he had Curry retreating into his corner. Nunn did not let him leave. He poured punch after punch into the challenger's head until Curry again crumbled to his knees. This time Nelson stopped the fight.