(FILE PHOTO) Rafael Nadal,Grand Slam champion, will retire from tennis at the end of this season. MELBOURNE, AUSTRALIA - JANUARY 29: Roger Federer of Switzerland waves to fans in the crowd as he poses with the Norman Brookes Challenge Cup after winning the Men's Final match against Rafael Nadal of Spain on day 14 of the 2017 Australian Open at Melbourne Park on January 29, 2017 in Melbourne, Australia. (Photo by Scott Barbour/Getty Images)