final blow? This isn't mortal kombat dude lol
. I don't know how much taller you are to the dude but I go for the solarplexus, ribs and sternum but I don't know about hitting him too hard in the sternum because those things have a habit of breaking easy on some people. Body shots are not really a final blow of sorts because of all the mass accumulates there but it is a good place to slow a person down because they have trouble breathing when they have to constantly brace for a blow there.