Floyd Mayweather Jr has reiterated his intention to retire from boxing following this Saturday's bout against Andre Berto.
Mayweather, who will equal Rocky Marciano's unbeaten record of 49-0 with victory over Berto, says that his health is now his top priority.
"If you stick around too long, anything can happen," Mayweather told reporters.
"I'm not really worried about losing, but I want to have a sharp mind. You can make a lot of money, but you still want to be able to walk and talk. Number 49 is my last fight."
The five-weight world champion also stated that his victory over Manny Pacquiao in May means there can now be no debate surrounding who holds the title of the world's 'best ever boxer'.
"They gave [Pacquiao] so many accolades, called him an all-time great, but all these people had to eat their words," said Mayweather.
"If he's an all-time great, then what does that make me? If they're saying he's the fighter of the century, what does that make me?
"I'm going to be 'the best ever' until the day I die."
Mayweather will look to equal Marciano's unbeaten record when he takes on Berto in the MGM Grand, Las Vegas, at around 4am BST on Sunday morning.