Say you are on a fight and your opponent is a wrestler or a bjj nerd and they come in for a takedown and they put there head into you for the takedown. In a street fight would it be effective to just hit the back of their head as hard as you can while they are trying to do a takedown. Would probably knock them out without having to go to the ground.

In a real fight all parts of their head are going to get smashed, their eyes are going to get poked, with legs and knees flying in all directions.

Crotch sniffer in a real fight: