Conor McGregor is seen by many as a legend in mixed martial arts, and his foray into boxing helped kick off the thriving crossover scene.
But one observer isn't buying into the hype.
Paulie Malignaggi, a former two-weight champion who was McGregor's sparring partner ahead of the Irish star's 2017 boxing match against Floyd Mayweather Jr., has long been criticial of the former two-division UFC champion and this week he reignited the war of words between the two men.
Speaking to Action Network about his rival, Malignaggi questioned McGregor's motivation as a fighter, attributing the 35-year-old's success to good fortune rather than good mentality.
"McGregor was lucky to achieve what he achieved in his career, physically and talent wise he's up there, but just because you can do a bunch of high kicks from a Jean Claude Van Dam movie, doesn't mean you're a fighter; you need guts, you need a willingness to succeed, you need a willingness to enter the trenches and if you don't have that, you're going to fade," Malignaggi said.
‘We've talked about AJ (Anthony Joshua) losing that edge, but McGregor is on a different level. McGregor will quit on you, he does quit. AJ does not take as many risks anymore but at least he's not quitting.
"McGregor is an outright quitter. He is a fighter that was not as good as advertised, there was great marketing behind him. And the money he's made now isn't helping, so you've got a problem - all he's going to do is continue to be a punching bag.
"If you're a punching bag in your twenties, you'll definitely be a punching bag in your thirties.”
Malignaggi continued by saying that McGregor was wise not to escalate their sparring rivalry into a real boxing match, as the American is confident it wouldn't have gone well for McGregor.
"I'm a better trash talker than McGregor, that's one of the reasons he did not fight me, I would have trashed him in the press conferences and the fight," he said.
"It would have ended all of the hysteria around him because I would have destroyed him in the trash talking and in the ring. I would have ruined the whole aura around him. He was smart not to pull the trigger on a fight with me."