"Right now I'm TBE (the best ever) and after this fight I will still be TBE. One fight against Pacquiao doesn't define my career," Mayweather said.

"The great thing about my career has been that I'm a smart businessman. Let's talk about that.

"A 19-year career with no punishment on the body and hundreds of millions of dollars in the bank? That's something to talk about.

"Absolutely the money means more to me than the unbeaten record - my daughter can't eat no zero. She can't spend a boxing record.

"The money is to make sure that my children and my children's children are secure and that they're okay. That's the most important thing.

"Within the last 48 hours I made 11million and that's going to my children. I've made a lot of smart investments.

"A lot of people say I'll have nothing when my career is over, but I make calculated moves."

Rocky Marciano's hallowed mark of 49 victories edges ever closer and even before the welterweight rivals have stepped into the ring at the MGM Grand, attention has drifted towards Mayweather's future.

Should fireworks or controversy dramatise Sunday's unification showdown, a September rematch in the final fight of Mayweather's deal with Showtime will be inevitable.

Equalling Marciano's record would place him on the brink of greatness, a label many are reluctant to bestow upon a fighter who has been criticised for his defensive style and for picking opponents too carefully.

An important voice advising him to retire is father and trainer Floyd Mayweather Sr and the bronze medal winner at the 1996 Atlanta Olympics is adamant that September will be his final outing.

"Only God can judge me. I've got two fights left," Mayweather said.

"People ask me about Rocky Marciano's record. He was one hell of a fighter and guys like him, Muhammad Ali and Sugar Ray Robinson helped pave the way for me to be where I am now.

"But no, I won't miss boxing. No. No, fifty is special for you, it's not special for me.

"We'll see how everything plays out. My father's entitled to his own opinion, but when all is said and done I'm my own man. But my father is right.

"September will be my last fight. It's time for me to walk away. Pacquiao two? No. Only God can predict the future."

Mayweather's defensive brilliance condemns him to being admired but never loved and it is the all-action style of Pacquiao that is capturing hearts and minds heading into the richest fight of all time.

However, Mayweather would rather concentrate on the long-term health benefits of his slick counter-punching style.

"A lot of people criticise me for being a defensive fighter, but on Monday night when I was sitting at home with my mother and daughter, I thought 'you know what, I'm proud of myself'," Mayweather said.

"To be in the sport for 19 years, the main thing is that I will get out with a sharp mind. I wasn't involved in a lot of wars, because being involved in a lot of wars puts a lot of wear and tear on your body.

"Even just training for fights of this magnitude puts a lot of wear and tear on the body. To still be sharp and have all my faculties, that's remarkable."