Serbia's Novak Djokovic plays a forehand return during his men's singles match against South Korea's Chung Hyeon on day one of the 2016 Australian Open tennis tournament in Melbourne on January 18, 2016. AFP PHOTO / SAEED KHAN-- IMAGE RESTRICTED TO EDITORIAL USE - STRICTLY NO COMMERCIAL USE / AFP / SAEED KHAN        (Photo credit should read SAEED KHAN/AFP/Getty Images)