Novak Djokovic of Serbia reacts during fourth round match against Gilles Simon of France on day seven of the Australian Open tennis tournament in Melbourne, Australia, 24 January 2016. EPA/FILIP SINGER
Novak Djokovic of Serbia reacts during the Men's Final against Andy Murray of Britain at the Australian Open tennis tournament in Melbourne, Australia, 31 January 2016. EPA/FILIP SINGER
Novak Djokovic of Serbia kisses his trophy after winning the Men's Final against Andy Murray of Britain at the Australian Open tennis tournament in Melbourne, Australia, 31 January 2016. EPA/FILIP SINGER
Novak Djokovic of Serbia in action against Gilles Simon of France during their fourth round match on day seven of the Australian Open tennis tournament in Melbourne, Australia, 24 January 2016 EPA/FILIP SINGER
Novak Djokovic of Serbia in action against Gilles Simon of France during their fourth round match on day seven of the Australian Open tennis tournament in Melbourne, Australia, 24 January 2016 EPA/FILIP SINGER
Novak Djokovic of Serbia serves the ball to Hyeon Chung of South Korea during the first round match of the Australian Open Grand Slam tennis tournament in Melbourne, Australia, 18 January 2016. The Australian Open tennis tournament runs from 18 to 31 January 2016. EPA/FILIP SINGER
Novak Djokovic of Serbia returns the ball to Quentin Halys of France during their second round match of the Australian Open Grand Slam tennis tournament in Melbourne, Australia, 20 January 2016. EPA/FILIP SINGER
Novak Djokovic of Serbia in action against Gilles Simon of France during their fourth round match on day seven of the Australian Open tennis tournament in Melbourne, Australia, 24 January 2016 EPA/FILIP SINGER