CARDIFF, Wales (AP) _ Unbeaten Welshman Joe Calzaghe held onto his WBO super-middleweight title Saturday when veteran Paraguayan Juan Carlos Gimenez failed to come out for the 10th round.

Calzaghe was on top from the first round, although he was unable to knock down a wily opponent who has never been dropped in 53 fights, including contests against Roberto Duran and the big-punching Nigel Benn.

Calzaghe continued the attack throughout the fight and rarely got hit by the counter-punching South American.

Gimenez took a stinging left-hand in the eighth round and was clearly losing the fight by the time it finished.

It was the first time in 53 fights that Gimenez, who had lost eight of his previous fights by decisions, failed to last to the final bell.

It was Calzaghe's second defense of a title he won by outpointing veteran Chris Eubank in October last year.

The Welshman was so in charge of the fight he was showboating in the third round, standing in front of his opponent and challenging Gimenez to hit an unguarded target. The Paraguayan simply didn't have the punching power to worry the champion although he lashed out with wild swings.

According to the judges, Gimenez didn't win one of the nine rounds.

Calzaghe's promoter, Frank Warren, revealed after the fight that Gimenez had been taken to hospital with a suspected broken rib.

``That was a very satisfying performance tonight,'' Calzaghe said. ``All credit to Gimenez, he's a really tough guy but I said I'd stop him and that's what I did.

``I'm learning all the time and I knew from the start that I'd have to be very patient with this guy because he is a very defensive fighter.

``I think I hurt him in every single round but I bided my time and I knew those body punches were breaking him up, and eventually he just couldn't carry on.''