LeBron James says Conor McGregor was "tough as a motherf**ker" during the Mayweather fight -- and joked there's no way in hell he coulda gone 10 rounds with TBE.
TMZ Sports was right outside the T-Mobile Arena when we spotted Bron and Cavs teammate J.R. Smith breaking down the fight.
LeBron: "You gotta respect [McGregor]."
Smith: "The thing is he came out strong in the beginning of every round. He burnt himself out."
LeBron: "You gotta respect him though because he ain't no boxer. Tough as a motherf**ker though."
Smith's retort was hilarious -- "Sh*t, give me $30 million! I'd be tough too for 30 minutes!"
LeBron: "I'm dropping in the 1st round. I ain't lasting 10."