So much for being obsessed with his rematch with Nate Diaz.

Conor McGregor, the MMA’s king of bombast, quit overnight, saying he was done with the sport.

Twitter went into overdrive with speculation about his reasons, but then UFC boss Dana White explained it away by saying that McGregor wasn’t happy doing promotional work for UFC 200 in July.

McGregor then spat the dummy. He didn’t just have a hissy fit; he stomped off because the UFC wouldn’t listen to him.

The Irishman has openly claimed he is bigger than UFC, a line the organisation was seemingly happy to indulge while he was winning and drawing fans in. But after Diaz belted him in March, his bluster lost its shine.

McGregor was properly schooled that night, although he had a chance to avenge that shattering loss in July, notwithstanding his dangerous tango with a higher weight division that brought him his first UFC loss. His oversized ego was crushed.

McGregor – and the UFC – paraded him as one of the all-time great fighters. Never mind that he has only fought for just three years at the highest level and has had just one career-defining fight (against Jose Aldo). The yardstick was limited.

If his retirement is permanent, his legacy will label him as a quitter. Given the chance to fight Diaz again, he walked away.

Say what you like about Floyd Mayweather. He went 49 fights unbeaten and bossed legendary fighters like Miguel Cotto, Manny Pacquiao and Oscar De La Hoya. He took his licks, too, and never ducked a challenge.

He was a real fighter.

McGregor? A flash in the pan with a handy line in cheap smack talk.