By Edward Chaykovsky

WBC/WBA welterweight champion Floyd Mayweather Jr. (48-0, 26KOs) is not worried about what he describes are "haters" - who are promising not to purchase his upcoming Showtime Pay-Per-View event against Andre Berto on September 12th at the MGM Grand in Las Vegas.

He feels some fans, and writers, are never satisfied with his opponent selections - and they always threaten to avoid his pay-per-view fights - but they always end up tuning in on fight night.

Mayweather expects the same thing to happen on September 12, with many of the critics and unhappy fans ponying up the $64.95/74.95 to watch what is being billed as the "final fight" of his 19 year career.

"They always tune in. They say one thing, but they do another," Mayweather said.

Mayweather has announced his retirement in the past. He issued a press release in 2008 announcing his retirement and then returned to the ring in 2009. He denies that he actually retired and claims this coming fight against Berto (30-3, 23 KOs) will be the real deal.

"We know that was nothing but a vacation," Mayweather.

He says Berto was selected because of his action style. Mayweather says he is training harder for Berto than he did for the May 2nd mega-fight with Manny Pacquiao, because he's motivated to close his career with a knockout victory.

"I don't know why, but I'm just training a lot harder for this fight," Mayweather said. "I just want to go out with a bang, I guess."