NEW YORK,  (Reuters) – Manny Pacquiao’s desire to  take on Floyd Mayweather may not be enough to persuade the  American to climb into the ring for a dream fight against the  Filipino, promoter Bob Arum said on Thursday.

As Pacquiao returned to a hero’s welcome in Manila yesterday following his impressive WBO welterweight title win over  Miguel Cotto at the weekend, Arum cast doubt on a Mayweather showdown, saying the American might not want to blemish his perfect record.

“But you have to understand Mayweather’s psyche,” Arum told  reporters at a lunch saluting Yuri Foreman, who became the first Israeli to win a world title when he claimed the WBA  super welterweight crown on the Pacquiao undercard.

“Psychologically he may not be prepared to do this fight,”  Pacquaio promoter Arum added. “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.”

The 32-year-old Mayweather, who has won titles at five  different weight classes, has a 40-0 career record while  Pacquiao, 30, improved to 50-3-2 when he stopped Cotto in the  12th round in Las Vegas.

HIGHER FIGURES

“He is afraid, terrified of losing that zero,” said Arum,  possibly in an effort to goad Mayweather into making the match.

“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.”

Pacquiao, who won his seventh world title in an  unprecedented seventh weight class, told a radio interviewer  this week he wanted to fight Mayweather in what would be a  showdown between the world’s two best pound-for-pound boxers.

However, the Filipino threw the ball back in Mayweather’s  court with comments to local media at Manila airport.

“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,” the Inquirer newspaper quoted him as saying on its  website (www.inquirer.net).

Mayweather’s last fight against Mexico’s Juan Manuel  Marquez in September, a victory by a unanimous points decision,  drew a million pay-per-view buys.

Final figures are yet to be released but Pacquiao’s  stoppage win over Cotto is widely tipped to have generated  more.

After being greeted by a media scrum at the airport,  Pacquiao rode a flat-bed truck adorned with flags around the  streets of Manila, drawing thousands of cheering fans.

Representatives of HBO Boxing expressed confidence that  Pacquiao and Mayweather would fight as welterweights in May,  and Arum said he would try his best to arrange it.

“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,” Arum said.