Floyd Mayweather retired from boxing in 2015 with a 50-0 career-record across five different weight classes.

He’s arguably the best fighter of his generation and is often mentioned in discussions about the best of all time.

At the age of 44, the former world champion continues to participate in lucrative exhibition fights and is set to return to the ring in yet another atop the iconic helipad at the Burj Al Arab Jumeirah hotel in Dubai next month.

There’s no doubting that Money remains in incredible shape for his age, something he may owe to a brutal defeat he suffered during a sparring session when he was 20 years old.

As reported by talkSPORT, Mayweather visited Paul Spadafore, a now little known American boxer who had just become the IBF lightweight champion, two years after he’d won the bronze medal at the Atlanta Olympics.

Mayweather had a 13-0 record at the time and was given the opportunity to get in the ring with the champion for a full six rounds.

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Enter Giveaway

However, Spadafore, who was just days out from his first defence of the IBF lightweight world championship, gave him such a battering that he tried to throw the towel in during the fourth round.

Jesse Reid, who was Spadafore’s trainer at the time, refused him however, forcing Mayweather to go the distance with the champ.

“It’s the reason he’s never out of shape. And [why] he never lets people tape his sparring,” Reid told FightHype some years later.

Describing the session, Reid said: “[Mayweather’s] nose is bleeding and that eye looks like it’s swelling up, and he [Spadafore] keeps crackin ’em.

“Finally in the fourth round Mayweather comes to me and asks me if he can get out of the ring because he says he’s tired.

“I says, ‘you ain’t getting out of the ring, you’re getting your ass kicked today to teach you for all the big mouth of you and your father’.”

At the time, Mayweather had only been fighting professionally for two years and wasn’t in great shape. Meanwhile, his opponent that day was 49-1-1 with his sole defeat coming in his penultimate fight and the draw in a world title unification fight.

According to Reid, the humbling Mayweather experienced taught him a valuable lesson; one that helped shape his incredible career and ensure he maintains the physique of a prize fighter even in retirement.