The Manny Pacquiao camp have raised the stakes with Floyd Mayweather Jr by insisting he is scared the Filipino would ruin his unbeaten record if the two meet in a pound-for-pound battle the boxing world is crying out for.

Pacquiao increased his claims to be the best pound-for-pound fighter on the planet with his 12-round demolition of Miguel Cotto landing him the WBO welterweight title in Las Vegas.

Mayweather returned to the ring with an impressive win over Juan Manuel Marquez in September and now the fight everyone wants to see is a battle between him and Pacquiao.

The 32-year-old American was undoubtedly the pound-for-pound king before his retirement but Pacquiao's continued success as he rises up the weights now has him firmly in the argument with opinion now split on who is the better fighter.

Mayweather insisted he was the better man earlier this week, and he said Pacquiao was afraid to face him.

However, the Filipino's trainer Freddie Roach believes his man will win any meeting between the two, whilst promoter Bob Arum says Mayweather is scared of losing his 40-fight unbeaten record.

"You have to understand Mayweather's psyche. Psychologically he may not be prepared to do this fight," said Arum.

"Now this is me being an amateur psychologist, but Mayweather is so tied up with the fact that nobody has beaten him, that he has a zero on his record, I don't know if he would be willing to go into the ring with anybody that could jeopardise that zero.

"He is afraid, terrified of losing that zero.

"That's why he's ducked (Shane) Mosely, (Antonio) Margarito and Cotto, and the question is will he duck Manny Pacquiao because he's so afraid of losing that zero."

Arum's goading is aimed at getting Mayweather into the ring, and American TV executives believe a super fight at welterweight next May is on the cards.

Pacquiao himself enjoyed his now customary hero's welcome as he arrived back at Manila airport, and he told Mayweather that he should be the one challenging for a fight.

"We are not pushing the fight. He should be the first to challenge me, after all I got a higher pay-per-view from my fight," Pacquiao told the waiting media.

Regardless of who challenges who, the fight must surely go ahead with the expected huge revenue if nothing else forcing the two men to get into the ring together.

"It's not so much that I give a damn whether this fight happens - I don't - and for me it's not the greatest experience doing a promotion with Floyd Mayweather," Arum added.

"But boxing is on such a roll now, not to do this fight would slow down considerably the momentum that boxing has, and that would be wrong."