It's probably just me, but I have never seen the 'sporting' side of this type of fighting.
I think a real boxer wouldn't let him or any of the others get close enough to ever be
effective or put them on the mat. A professional boxer would have him, and any others that are like that out in less than a minute.
Except for Muhammad Ali.
I would have to say, fifteen (15) seconds or less after the first round bell rings.