Manny Pacquiao will undergo surgery on a shoulder injury this week and could be out of action for up to a year following his unanimous points defeat by Floyd Mayweather, according to reports in the United States.
Pacquiao could also face a possible fine or suspension after answering 'no' on a Nevada Athletic Commission (NAC) questionnaire ahead of the welterweight unification showdown in Las Vegas last Saturday.
He did not submit any injuries before the fight, but cited a shoulder problem after it.
''We were planning to postpone because for two weeks I didn't train well. We couldn't do what we wanted to because of my shoulder,'' Pacquiao said after the bout.
''From the third round I felt the pain in my shoulder. When I threw a lot of punches it hurt, so I backed off."
He could now be set to spend time out of the ring while he recovers.
A host of Hollywood A-listers and sports stars gathered at the MGM Grand to watch Floyd Mayweather comprehensively outpoint Manny Pacquiao in their eagerly-awaited superfight.
Veteran actors Clint Eastwood and Robert De Niro received the two biggest cheers from the 16,507 when footage of them walking into the arena was televised on the big screen.
At the younger end of the Hollywood spectrum were heavyweight trio Christian Bale, Jamie Foxx, Ben Affleck and Bradley Cooper, while Drew Barrymore also watched the weltwerweight rivals in action.
Music royalty were also in attendance as Jay Z and Justin Bieber turned up.
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Former heavyweight world champion Mike Tyson hailed "invincible" Floyd Mayweather after his dominant points victory over Manny Pacquiao at the MGM Grand in Las Vegas.
Mayweather was too classy for his Filipino opponent, with the scorecards of 118-110, 116-112, 116-112 showing how good the American was.
And Tyson, the former undisputed world champion, believes Mayweather is untouchable in the welterweight division.
"I think he (Mayweather) won the fight, he was pop-shoting Manny. Manny had a good beginning but he (Mayweather) controlled it," Tyson told Sky Box Office.
"He controlled the fight, he has great endurance (and) he did a real good job.
"It's his era, his time. He is in invincible mode now - no-one can stand with him at this particular moment."
Undefeated Floyd Mayweather Junior has heaped praise on his opponent Manny Pacquiao following his unanimous points victory in Las Vegas.
He's a hell of fighter, he's one of the guys at the pinnacle in sport of boxing
I know he was going to push me. He had moments in the fight. I wasn't getting hit with a lot of shots.
He is a tough competitor, I have got to take my hat off to my dad without him I wouldn't be here.
Floyd Mayweather has beaten Manny Pacquiao by a unanimous points decision in their unifying welterweight title clash in Las Vegas.
The 38-year-old American withstood an aggressive start by the Filipino and relied on his renowned defence and counter-punching to dominate the 12 rounds as he improved his career record to 48-0.
Manny Pacquiao and Floyd Mayweather Jr. have begun their "fight of the century" bout at the MGM Grand in Las Vegas.
Manny Pacquiao and his mother share a pre-fight prayer ahead of the Mayweather fight at Las Vegas' MGM Grand Garden Arena today.