Floyd Mayweather is one of the few high-profile champions to retire from the sport of boxing undefeated.
The likes of Joe Calzaghe and Rocky Marciano, the only heavyweight champion to retire undefeated, are in good company with Mayweather, as none of them tasted a loss in their career. However, they still faced top opposition.
For Mayweather, he can boast wins over the likes of Oscar De La Hoya, Manny Pacquiao, and Ricky Hatton as he dispatched the greatest fighters of his era. Even in terms of modern great Canelo Alvarez, ‘Money’ can claim victory.
To set up his blockbuster fight with the Mexican, however, Mayweather would have to get past a title challenge from a former champion.
Floyd Mayweather defeated Robert Guerrero in 2013 via decision
On May 4th, 2013, Mayweather would be obligated to take on mandatory challenger Robert Guerrero. The pair would meet for the WBC World Welterweight title, as they competed in Las Vegas.
Mayweather went into the bout after a victory over Miguel Cotto and a record of 43-0. As for the challenger, Guerrero had retained the WBC interim title against Andre Berto in his last fight.
Against Mayweather, he was looking to improve his record to 32-1-1.
However, the challenger would suffer just the second defeat of his career as Mayweather was a step too much for Guerrero. Despite a hearty opening from the former two-division champion, Mayweather would retain his title.
Settling into the fight after the opening rounds, Mayweather could dictate the bout, winning on the judges’ scorecards. Not only would the victory improve Mayweather’s winning streak, but it would also set up a huge meeting with Alvarez.
Floyd Mayweather fought and defeated Canelo Alvarez in 2025
Although Alvarez is still involved in huge fights in the year 2025, he has been used to being a headliner for over a decade. In 2013, he was involved in one of the biggest fights he would ever have in his career.
Meeting in a super welterweight unification bout, both Alvarez and Mayweather went into their September 2013 meeting as champions. Alvarez defeated Austin Trout in his previous outing before facing Mayweather.
The two fought in Las Vegas, as Mayweather looked to hand one of the greatest Mexican fighters of all time his first loss.
Despite the bout being officially scored a majority decision, it was considered to be a convincing showing from Mayweather. Out-striking the Mexican, Mayweather would claim Alvarez’s WBC title, while defending his WBA belt.