Bob Arum says Floyd Mayweather will duck Miguel Cotto if he thinks there's a chance of losing.

P4P king Mayweather (39-0) retained his WBC welterweight crown with a crushing 10th-round knockout of Ricky Hatton in Las Vegas on Saturday night.

Meanwhile Cotto (31-0) cemented his position as WBA king by outpointing Shane Mosley at Madison Square Garden last month.

A meeting of the two unbeaten stars seems to be the next logical megafight as big-time boxing enjoys a golden renaissance.

But Arum, whose Top Rank promotion company now has Cotto and had an ugly split with Floyd back in 2006, says it still might never happen.

He accused Mayweather of "the biggest con game ever", and told the Los Angeles Times: "If (Mayweather) thinks he has a chance to lose, he won't take a fight.

"He's afraid to lose, and that's a horrible, horrible thing...Anyone who's not realising that's what's happening with Floyd is moronic."

Mayweather himself refused to confirm he'd fight again, and says he's set to take a long break from the ring.

"Just to be the face of boxing is a blessing, but I have to walk away. I was once told never to let boxing retire you."

Meanwhile Mayweather's adviser Leonard Ellerbe says Arum's taunts are merely sour grapes, claiming: "Arum's a bitter old man because Floyd outsmarted him."

Meanwhile Cotto must sit and wait to see if he'll get the megafight that could catapult him to worldwide stardom, just as it did for Mayweather in 2007.

"If you ask Floyd to fight with me, he always has an excuse," Cotto said.

"I'm not attracting enough fans. I don't represent too much money. He's not correct, though. He knows who Miguel Cotto is."