Floyd Mayweather has dismissed suggestions that a year out of the ring has left him vulnerable against Robert Guerrero in their WBC welterweight title showdown in Las Vegas tomorrow night.

Mayweather has not fought since his unanimous decision win over Miguel Cotto last May, and also served two months of an 87-day prison sentence for domestic abuse.

But Mayweather shrugged off claims by Guerrero that his inactivity would have any impact on his performance - and repeated his conviction that he is one of the best fighters in the history of the sport.

Mayweather said: "I feel unbeatable. I'm not going into a fight thinking I'm beatable. I'm in this sport to go down as the best, and to do what I feel capable of doing.

"If that's the way (for Guerrero) to build his confidence, to get himself mentally prepared, then more power to him. But I'm in tip-top shape. I've been been in the gym working hard.

"You don't get to the pinnacle by not facing and fighting the best competition. I beat everybody in the 90s and I beat everybody in the 2000s, and here I still am 17 years later.

"My main focus is to win. I focus on winning and I'm always going to control the tempo of any fight because of my experience."

"I feel unbeatable. I'm not going into a fight thinking I'm beatable. I'm in this sport to go down as the best" - Floyd Mayweather

Mayweather starts a big favourite against Californian Guerrero, who boasts 31 wins from 35 fights, including a solitary loss to Gamaliel Diaz in a featherweight fight in 2006.

But Guerrero is determined to shatter what he sees as Mayweather's fake aura of invincibility, and says his strong faith and his own battle against adversity following his wife's diagnosis with leukemia will help him score a momentous upset.

Guerrero said: "You get a lot of people out there that think Floyd's like a god, that's he's unstoppable and there's no blueprint to beat him.

"But being a big believer in God, there's a blueprint for everybody. There's a way to conquer anything.

"This is the moment, with a guy that nobody thinks can be beaten, saying he's unstoppable and the best ever. God's put me in this position for a reason and he's groomed me to take over in boxing."