Mayweather will risk his World Boxing Council welterweight title when he goes up against Guerrero on Saturday.
Mayweather, 43-0 with 26 knockouts, went to jail last June for domestic violence and since his release eight months ago has been working to regain the fitness needed to defend his place atop the list of boxing's moneymakers.
"I feel unbeatable," Mayweather said. "I'm in tip top condition. I'm in great shape. I have been working hard. I just call it a vacation. Sometimes the body needs time to heal. The body needs time to rejuvenate. The body needs time to rest."
But fellow American Guerrero, 31-1 with 18 knockouts and a 15-fight win streak dating to 2005, sees himself as having been given this opportunity in order to humble Mayweather by inflicting the first loss of his career.
"Not just humble Floyd but humble the boxing world," Guerrero said of his mission. "Some people think Floyd is a god with the way he lives, the way he spends money. Some people think he is unbeatable.
"That 0 has to go. He's going to have his first loss."
And Guerrero thinks the layoff will have more of an impact on Mayweather than he will admit.
'Shake that ring rust off'
"Having that year off, you have that ring rust," Guerrero said. "It's going to take a little time to shake that ring rust off. Being a whole year's layoff, he's going to feel the punches more."
Mayweather plans on making The Ghost feel a few blows as well.
"Everybody always says what they're going to do to me," Mayweather said. "He is a solid opponent. He talks a good game. Now we have to see if he can fight as well as he talks. He's more like a grappler, a wrestler, than a boxer."
Guerrero comes off a 12-round decision over Andre Berto last November and expected Mayweather to be formidable, ring rust or not.
"Floyd is a very smart fighter and a very sharp guy. I look forward for him to be ready to go," Guerrero said. "If he is slowing down, his slower is faster than almost every other guy out there."
Mayweather has his father, Floyd snr, as his trainer for the fight and the elder Mayweather has exchanged harsh words with Guerrero's father Ruben in pre-fight promotions.
'Beat up the woman beater'
"We're going to beat up the woman beater," Ruben Guerrero said of his son facing Mayweather.
"I don't have to fight his father," the younger Mayweather said. "Like I told my dad, just carry yourself in a classy way."
Helping boost Mayweather's pay-per-view purchase numbers on the Mexican Cinco de Mayo holiday, will be a Mexican showdown undercard title bout between unbeaten challenger Abner Mares, 25-0 with one drawn and 13 knockouts, and World Boxing Council featherweight champion Daniel Ponce de Leon, 44-4 with 35 knockouts. – AFP