When Khabib Nurmagomedov retired undefeated as the UFC lightweight champion in October 2020, his reasons for doing so were very clear.

Following the passing of his father and coach Abdulmanap Nurmagomedov earlier in the year, Khabib promised his mother that his UFC 254 title defence against Justin Gaethje would be his last fight.

Khabib looked as good as ever in the contest - submitting Gaethje inside two rounds. However, immediately following the contest, the 32-year-old shared his promise to his mother with the world, confirming that he would no longer compete.

At the time, it was clear that Khabib was leaving a lot of money on the table by walking away from combat sports - and recently it was revealed just how much.

In an interview on Mike Tyson's Hotboxin' podcast, Khabib's manager Ali Abdelaziz confirmed that his client recently turned down a nine-figure sum to square off with Floyd Mayweather, presumably in a boxing match.

"Khabib got offered $100 million after he was retired to fight Floyd Mayweather. $100 million," said Abdelaziz, per bleacherreport.com. 

"You can ask Floyd, you can ask everybody, and Khabib said, 'No, I'm retired. I told my mother I'm retired. I'm gonna keep my word to my mother. If my mother told me to fight again, maybe I will, but right now she told me not to fight.' He comes from a Muslim culture. We respect our mothers very dearly. We can't go to heaven without our mother's permission."

Elsewhere in his chat with Tyson, Abdelaziz suggested that Khabib had previously been offered a similar sum for a rematch with Conor McGregor, but had also rejected that bout.

Following Khabib's retirement, UFC president Dana White made a number of attempts to convince 'The Eagle' to fight again. White was hopeful of getting Khabib back in the Octagon at least one more time to potentially take his professional record to 30-0.

However, Dana admitted defeat in his quest after almost six months of trying - and now seems certain that Khabib will never fight again.

Abdelaziz also poured cold water on recent rumours that his fighter could be tempted into a return for a bout against MMA legend Georges St-Pierre. Now 40 years old, 'GSP' would struggle to match Nurmagomedov's level, according to Abdelaziz.

It seems, then, that we have definitely seen the last of Khabib.

If $100 million is not enough to convince him to lace up a pair of gloves again, no amount of money will be. In truth, Nurmagomedov has never seemed particularly motivated by financial wealth anyway.

Floyd Mayweather moves on to face Logan Paul on June 6 and Khabib will continue to enjoy his retirement.