Sugar Ray Leonard Says Ali is the G.O.A.T., Mayweather Ain't

Floyd Mayweather is wrong when he calls himself THE BEST EVER ... because, according to Sugar Ray Leonard, there's only one guy in that discussion ... the great Muhammad Ali.

A little backstory here ... Mayweather and Leonard ain't exactly the best of friends, having exchanged several barbs over the years over boxing, and the fact the Sugar Ray KO'd Floyd Sr.

The two men even reportedly traded insults IN PERSON once ... with Floyd reminding Leonard he's TBE, and Leonard telling Floyd he'd KO him just like he did his father.

Even still ... Sugar Ray has always been complimentary of Floyd as a boxer, so when we got him out in NYC we thought it was fair to ask him if Money has a legit claim to calling himself TBE.

"Muhammad Ali. Without question."