People overestimate the fragility of the egos of these guys. How many slam finals did Lendl lose before he won a boatload of them? How far did guys like Agassi and Sampras slip down the ladder before climbing back to the top? You don't get as far as Djokovic has gotten by having an ego made of delicate crystal.
"I may be synthetic but I'm not stupid"
Bishop, in "Aliens"