Two days after saying he would be open to a re-match with Manny Pacquiao, unbeaten American Floyd Mayweather Jr reversed course on Thursday (7 May) describing the Filipino as "a sore loser".

In an interview with Showtime to be broadcast on Saturday, Mayweather expressed his disgust that Pacquiao had blamed an injured right shoulder for his defeat by the American in the so-called Fight of the Century in Las Vegas.

Pacquiao, the former eight-division world champion, lost a unanimous decision to Mayweather on Saturday in the richest prize fight ever before undergoing successful arthroscopic surgery on his right shoulder four days later.

"I'm not going to buy into the bul**** ... and I don't want the public to buy into the bull****," Mayweather said in quotes released by Showtime on Thursday.

"He lost. He knows he lost. I lost a lot of respect for him after all of this."

Asked by Showtime whether he had noticed Pacquiao being hampered by his shoulder during their 12-round bout at the MGM Grand Garden Arena, Mayweather replied: "Absolutely not."

He then added: "He was fast. His left hand was fast. His right hand was fast and he was throwing them both fast and strong. Excuses, excuses."

On Monday, an MRI scan in Los Angeles confirmed the Filipino had a torn rotator cuff and on Wednesday he underwent surgery.

Earlier this week, Mayweather said he would be willing to give Pacquiao a rematch next year, telling ESPN's Stephen A Smith that he would delay his proposed retirement from the sport.

"I will fight him in a year after his surgery," Mayweather told Smith in a text.

On Thursday, however, the 38-year-old American made a complete U-turn on that statement.

"Did I text Stephen A Smith and say I will fight him again? Yeah, but I change my mind," said Mayweather.

"At this particular time, no, because he's a sore loser and he's a coward... If you lost, accept the loss and say, 'Mayweather, you were the better fighter'."

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