Tyson had a perfect punch. That made up superbly for his deficiency in height and reach in his division. He would cock his arms and, instead of throwing his punches, he 'pops' them like a gun, and also puts his whole body into his punch as if leaning on to it - he uses his whole body as an anchor for his explosive punches. You can see that, for example, when he landed a perfect punch against Andrew Golota. A brawler like Hagler would be a good target for his punches.