You have to be better than him. Sorta why only Fedal have a winning h2h on him.
Federer can hit him off the court if playing well, and Nadal can make him run so much and counter most of DJokovic's tactics.
Basically, someone who moves and attacks well, but also has the ability to mix up the game.
"And what if there IS a difference? The fact is I heard a difference, regardless if there actually is a difference or not."