Floyd Mayweather insists he will not allow his record $41.5million purse to become a distraction when he defends his unbeaten record against Mexico's Saul Alvarez in Las Vegas on Saturday night.

Mayweather's 45th professional fight is set to smash all-time pay-per-view records as he squares off against the also-unbeaten Alvarez at the MGM Grand Casino.

Mayweather said: "I'm not focused on the money or anything. I'm focused on going out there, performing well and giving the fans what they want to see - it's about excitement."

It is perhaps a mark of the grudging respect in which Mayweather holds the 23-year-old Alvarez that he has resisted much of his usual trash talk during fight week.

The Mexican's own 43-fight winning record has been hyped to the hilt in order to help drive pay-per-view sales and some good judges in the sport believe he stands as good a chance as anyone of inflicting Mayweather's first defeat.

But Mayweather retorted: "I've been here before so I know what it takes. He's 42-0, but he hasn't faced 42 Floyd Mayweathers, otherwise he'd be 0-42.

"September 14 is just another stepping stone, just another opponent to me. He knows he's facing Floyd Mayweather, but I know I'm facing just another opponent."

Now 36, Mayweather has popped in and out of so-called retirement in recent years and his fight with Alvarez will be the first time he has fought twice in the same year since 2007.

He outpointed Robert Guerrero in their WBC welterweight title fight in Las Vegas in May but is moving back up to light-middleweight to take on Alvarez, who has campaigned all his top-flight career at the weight.

Alvarez said: "When you fight Floyd you have to be ready for every aspect of a fight. You have to be able to adjust mentally as well as physically. I have to be very, very smart.

"We've prepared like never before. Floyd is a fighter who throws five punches a round and he lands them - that's why he wins rounds. But we're prepared for that - we're prepared for everything."

Even a naturally bigger Alvarez may not have the power to trouble Mayweather. Matthew Hatton dragged him the distance in March 2011 and three months later Ryan Rhodes also lasted to the final round.

Mayweather added: "If the game-plan is to outbox me, nobody can outbox me. You have to be able to out-match me mentally, and I'm the strongest mental fighter in the sport of boxing.

"I guess other great fighters look at it as, you win some, you lose some. Me, I look at it as I want to win them all. I'm a winner. I don't lose. Some day he will go down in the Hall of Fame - as one of the opponents I beat."