Floyd Mayweather delivers stinging criticism of Muhammad Ali

IT'S almost a pointless argument because they are from different eras and different weight divisions, but American Floyd Mayweather has ignited the 'who's the greatest' debate by suggesting he is a better fighter than Muhammad Ali.

With his match-up against Filipino Manny Pacquaio - set to be the highest-grossing fight in the sport's history - to be held in Las Vegas on May 3, Mayweather was asked by ESPN's Stephen A Smith if he thought he should be ranked ahead of Ali.

The reply was not surprising given the outspoken 38-year-old is the best self-promoter since the heavyweight champ.

"You gonna tell me that it's cool to lay on the ropes and take punishment and let a man tire himself out from beating you, and then he basically fatigued? You hit him with a few punches and he go down and quit, and you want to be glorified for that?"

Mayweather is rated by most commentators as the best pound-for-pound fighter in the world, although Pacquiao's trainer Freddy Roach recently contended the American had "ducked" too many quality opponents to be considered the greatest in recent times.

"Mayweather is undefeated so you have to give him a little credit for that. But he has picked and chosen his opponents and I don't think he's fought enough competition to be considered the best. You have to fight the best to be the best," Roach told the Daily Mail.

That was one thing you could never accuse Ali of - he took on and beat the best in a golden era of boxing.