Keith Thurman says Floyd Mayweather is straight CHICKEN -- accusing the boxing legend of running scared before he retired and now he's calling Floyd out.
"If he wanted a real fight, he would have saw me years ago," Thurman tells TMZ Sports.
"You never wanted to fight me. I was right there right underneath you for years. I was the #1 contender of the WBA and then they made you super champion so that our names didn't have to be in the same sentence together."
FYI, a WBA Super Champ is a fighter who holds multiple titles in the same division -- and is exempt from mandatory title defenses. Essentially, Super Champs can pick their own opponents.
Thurman says during Floyd's active fighting days, there were plenty of opportunities to make a fight between the two ... but Mayweather wussed out and didn't want the smoke.
Now, Thurman -- who's 29-0 -- is gearing up for the biggest fight of his career against Manny Pacquiao on Saturday ... and he knows a victory could open some huge doors.