Former undisputed world heavyweight champion Mike Tyson claimed Floyd Mayweather Jr was "delusional" for claiming he is better than Muhammad Ali.

Tyson was interviewed on Thursday regarding Mayweather's fight against Manny Pacquiao on Saturday.

When the discussion turned to comparing Mayweather with Ali, Tyson went off.

"He's very delusional," Tyson told Undisputed Champion Network.

"If he was anywhere near that realm [of being as great as] Ali, he'd be able to take his kids to school by himself. 

"He can't take his kids to school by himself, and he's talking about being great?

"Greatness is not guarding yourself from the people, greatness is being accepted by the people. He can't take his kids alone to school by himself. He's a little, scared man. A very small, scared man."