Ross Purrity was slower and had less power than Tyson and he KO'd Wlad!
So what does that mean?
Buster Douglas also had a better chin than Wlad.
And no Tyson wasn't in his prime in this fight. Tyson had already left his original trainer Kevin Rooney,spent time drinking,banging *****s in Japan and doing no boxing training. Tyson was even dropped in sparring before the Douglas fight.
Tyson was already on the decline.