4 or 5 rounds? Sosnowski who was unknown undeserving and not very good lasted 10 rounds! Adamek went 10. Old Briggs lasted the full 12. Chisora and Johnson lasted 12. Fat slow Sam Peter even lasted 7. Charr is not very talented but he is a solid average heavyweight. Vitali's power is gone and he wasn't a one punch KO artist to begin with. If Vitali gets a ref stoppage TKO in round 10 or 11 he will be lucky.
Why is it a foregone conclusion that this is going to be his last fight? Has he specifically said so?