(FILE PHOTO) Rafael Nadal,Grand Slam champion, will retire from tennis at the end of this season. GENEVA, SWITZERLAND - SEPTEMBER 20: Rafael Nadal of Team Europe waves to fans as he is introduced during Day One of the Laver Cup 2019 at Palexpo on September 20, 2019 in Geneva, Switzerland. The Laver Cup will see six players from the rest of the World competing against their counterparts from Europe. Team World is captained by John McEnroe and Team Europe is captained by Bjorn Borg. The tournament runs from September 20-22. (Photo by Clive Brunskill/Getty Images for Laver Cup)