He kos a human punching bag with a left hook and all of a sudden you are comparing his power to Tyson?
Force = Mass * Acceleration. Wlad has slightly more mass, he's a little heavier than Tyson. Tyson had much greater acceleration because of his speed advantage over Wlad. I'd say Tyson's acceleration on his hook was much greater than Wlads, whereas Wlads mass only slightly greater than Tyson's. So, I think Tyson's left hook was harder than Wlad's.