Conor McGregor said referee Robert Byrd was wrong to stop his super-fight with Floyd Mayweather in the 10th round.
The UFC lightweight champion, 29, was beaten in his first professional boxing bout as 40-year-old Mayweather took his perfect career record to 50-0.
Irishman McGregor, who said he will return to the UFC but did not rule out boxing again in the future, said he was “just a little fatigued”.
“I thought it was close. I get a little wobbly when I’m tired,” he said.
“The referee could have let it keep going, let the man put me down. I am clear-headed.
“Where were the final two rounds? Let me wobble to the corner and make him put me down.”
McGregor had the best of the early rounds but former five-weight world champion Mayweather said that was part of his “game plan”.
“He’s not that fast, he’s not that powerful, but boy is he composed in there,” added McGregor.
“I thought it was close and I thought it was a bit of an early stoppage. I was just a little fatigued.
“I have to give it to him, that’s what 50 pro fights will do for you.”