His ability to judge situations

Be it his numerous Grand Slam wins or any other match. One of the great abilities of Federer is that he can adapt and react to a situation pretty quickly. Take the 2012 Wimbledon final against Andy Murray for example. Federer had lost the first set in a very unholy manner and the second set was dragged into a tie-breaker. However from there, it was all Federer express. His ability to come on top in a tiebreaker, and eventually the match, proved that he is the real deal. Federer can easily understand situations can make changes accordingly; this is one of the biggest events in his game.