Djoko's form dropped off massively from 2011, still he was the best in the world but Fed more than held his own, and it was still close by the end of the year the fight for the #1 ranking. AO courts will favor Djokovic should they meet, but I've always believed in Fed, and trust that he'll find a way or at least make it a battle.
Roger Federer. Paolo Maldini. Tom Brady. Wilt Chamberlain. GOATs.