US Open champion Novak Djokovic has picked-up a few nicknames through his career so far, but the one that has stuck is 'The Djoker'. And it's not really hard to guess why, considering the man who's all business on the tennis court never gives up an opportunity to play the fool off it. Video courtesy: NDTV

Balle Balle in 2012 US Open Video courtesy: NDTV