Conor McGregor UFC
Hall of Fame boxer Sugar Ray Leonard thinks Conor McGregor would get knocked out in the first round of a fight against Floyd Mayweather. Pictured: McGregor addresses the media during the UFC 205 press conference at Madison Square Garden on Nov. 10, 2016 in New York City. Getty Images

It’s hard to believe that Conor McGregor would have a chance to win a fight against Floyd Mayweather, and one former boxer thinks the bout would be over shortly after it starts. Sugar Ray Leonard predicted that the UFC star wouldn’t last very long against the best boxer of his generation.

“One round,” Leonard told TMZ when asked how long McGregor could survive against Mayweather.

READ: Conor McGregor predicts he will knock out Floyd Mayweather

Leonard certainly isn’t alone in his thinking. Shortly after McGregor won his last fight to become the UFC lightweight champion, famed trainer Teddy Atlas said on ESPN that McGregor couldn’t beat a “C-level” fighter, and he would only last “as long as Mayweather would allow him to last for.”

Mayweather is certainly an A-level fighter, and the oddsmakers seem to agree with that assessment. Around the time of Atlas’ comments, Jeff Sherman, who manages the Westgate SuperBook in Las Vegas, said McGregor would be a +1100 underdog in a potential super-fight.

McGregor, however, might be convincing some of the public that he has a real chance with all of his trash talking. The UFC fighter recently promised that he would shock the world against Mayweather, and McGregor is down to a +525 underdog at Bovada.lv. The online betting website gives Mayweather -850 odds.

If any UFC star has the skillset to become a successful boxer, it might be McGregor. While many MMA fighters are known for their wrestling or grappling, McGregor is best on his feet and one of the UFC’s best strikers.

Still, it seems nearly impossible that he would become the first fighter to defeat Mayweather, doing what the likes of Manny Pacquiao, Canelo Alvarez and Oscar De La Hoya could not.

Even though McGregor doesn’t have a legitimate shot to beat Mayweather, that doesn’t mean the bout won’t happen. Add Leonard to the list of people that think the fight will take place. UFC president Dana White and Hall of Fame trainer Freddie Roach are just a few others that expect McGregor and Mayweather to meet in a boxing ring.

Mayweather has called for the fight to happen in June, while McGregor has said the bout could take place in September of this year.