Forty-three previous fighters have failed to achieve what Gilroy's Robert "The Ghost" Guerrero hopes to pull off Saturday night at the MGM Grand in Las Vegas.
"Man, I'm ready," Guerrero said. "Floyd Mayweather's record is going to get broken, he's going to have his first loss. Better believe that."
The oddsmakers don't believe it. They have installed Mayweather (43-0, 26 knockouts) as a heavy favorite to stay perfect at the expense of Guerrero (31-1-1, 18 KOs) in their WBC welterweight title bout.
Mayweather, who has held at least one world championship belt continuously since 1998, was listed this week by the MGM Grand sportsbook as minus-700 (bet $700 to win $100) to win, while Guerrero is plus-475 (bet $100 bet to win $475).
None of it dents the confidence of Guerrero, a six-time, four-division world champion who understands the Showtime pay-per-view event is the biggest fight of his life.
Guerrero said he will be unaffected by the sideshow aspects to the bout, including a Wednesday news conference tirade by his father, Ruben Guerrero, who called Mayweather a "woman beater."
"It's fight time," he said. "All this stuff here doesn't mean nothing."
Guerrero isn't the first man who believed he could beat this generation's top pound-for-pound fighter. Mayweather has survived everyone's best punch -- often eluded it -- and maintained an unblemished record.
"There isn't a blueprint on how to beat me," Mayweather said. "No one has found a way to break the Mayweather code."
So what factors must come into play for Guerrero to have at least a chance to deliver the upset?
This is Guerrero's big moment, a fight he secured perhaps because he caught Mayweather's attention by handing Berto just his second defeat. Mayweather claims he'd never heard of Guerrero before then.
Guerrero isn't buying it, especially after Mayweather insisted on a rematch clause.
"It's like he says, 'I don't know who Robert Guerrero is, but I want a rematch.' Sure," Guerrero said. "He knows what he's getting into."
They both do.