If the fight had been two rounds, he would have won, he decisively controlled and won the first and most of the second. He was acting like a cocky mofo for a lot of the fight and got caught in the third and didnt recover, he has never been the most iron chin, remember when chuck ko'ed him?
If he needs to retire so does fitch, rashad, yves, etc just talking about last night. Unexpected things happen in fights, its what makes the sport so exciting. If he gets finished in his next two I'll agree but right now... no.
And let's not set aside the various chemical factors involved, for all we know he'll be legit on TRT like a lot of the UFC by his next fight.
His helmet was stifling, it narrowed his vision. And he must see far. His shield was heavy. It threw him off balance. And his target is far away.