The key here is "Prime for Prime." I'm not saying it would be easy, but no matter how tough Vitali is , Tyson KO's him. I think Tyson was underrated, yes underrated as a technically gifted fighter. His head movement, the way he got inside guys much taller than him and his power/torque were amazingly freakish.
I'm sure a lot of people will think the longer it went , the more chance Tyson would gass it, but remember, we're talking Prime.