I don't think it was mainly due to Floyd but he certainly did some damage.
I remember watching the hours leading up to the fight and Floyd was nowhere to be seen and it looked to be touch and go as to whether he would turn up or not. Hardly a situation to put a fighter at ease and put him in the mindset for the biggest fight of his life.
Having said that Hatton brought it on himself for mistreating Graham and casting him aside then hiring a totally unsuitable trainer!