Fury irritates the hell out of Mike for three rounds, smothering him from above as best he can, making him miss but not landing much substantial. In the fourth Mike lands a hideous right. Fury bounces off the canvas twice and the ref stops it when he looks in his eyes.
Strangely I think the size advantage works against Fury. If you take them at his word Fury is 6'9" and Tyson is 5'10". Fighting out of the peak a boo couch Mike was around 5'8". This means Fury is punching down about a foot, at such an angle that his chin is exposed to those incredibly fast hands of Mike.