Floyd Mayweather is lashing back at Canelo Alvarez -- saying beating Canelo's ass in 2013 was the easiest fight of his career ... and that includes the Conor McGregor fight.
Remember, Canelo told TMZ Sports that Floyd is hurting the sport of boxing by mixing it up with MMA stars like Conor and Khabib Nurmagomedov.
Canelo told us if Floyd is serious about fighting, he'd schedule a rematch so the two could settle an old beef.
Speaking of beef, that's where Floyd started his attack on Canelo moments ago -- posting a pic from their 2013 match and saying, "It didn’t matter if Canelo ate his PED steak or not this night, this was by far the easiest fight of my career!"
The PED shot is obviously a reference to Canelo's positive PED test before the GGG rematch, which Canelo blamed on tainted Mexican beef.
But, Floyd wasn't done ... he continued the attack, "Connor McQuitter was a way better fighter than Canelo's cheating ass and I beat the breaks off him too!"
Floyd also attacked Canelo's new $365 million contract -- which requires Canelo to take 11 fights in 5 years.
"It takes me 36 mins or less to make $300 million plus. It literally takes me 1 night and 1 fight to make what you might make in 5 years and 11 fights! So really, who's still winning? You do the math!"
Sounds like a fight that should be settled in the ring!!!