![Roger Federer of Switzerland returns to Rafael Nadal of Spain during their final match of the Monte Carlo Open Tennis tournament in Monaco, Sunday, April 23, 2006. Federer won (AP Photo/Patrick Gardin Roger Federer of Switzerland returns to Rafael Nadal of Spain during their final match of the Monte Carlo Open Tennis tournament in Monaco, Sunday, April 23, 2006. Federer won (AP Photo/Patrick Gardin](https://c8.alamy.com/compfr/2pd5ph8/roger-federer-of-switzerland-returns-to-rafael-nadal-of-spain-during-their-final-match-of-the-monte-carlo-open-tennis-tournament-in-monaco-sunday-april-23-2006-federer-won-ap-photo-patrick-gardin-2pd5ph8.jpg)
Roger Federer of Switzerland returns to Rafael Nadal of Spain during their final match of the Monte Carlo Open Tennis tournament in Monaco, Sunday, April 23, 2006. Federer won (AP Photo/Patrick Gardin
![FILE: Roger Federer of Switzerland reacts after winning the men's single final against Rafael Nadal of Spain at the Australian Open tennis tournament in Melbourne, Australia on Jan.29, 2017. Former world number FILE: Roger Federer of Switzerland reacts after winning the men's single final against Rafael Nadal of Spain at the Australian Open tennis tournament in Melbourne, Australia on Jan.29, 2017. Former world number](https://c8.alamy.com/compfr/2njarrj/file-roger-federer-of-switzerland-reacts-after-winning-the-mens-single-final-against-rafael-nadal-of-spain-at-the-australian-open-tennis-tournament-in-melbourne-australia-on-jan-29-2017-former-world-number-one-in-mens-tennis-roger-federer-announced-his-intention-to-retire-41-year-old-roger-federer-has-claimed-20-grand-slam-titles-the-yomiuri-shimbun-via-ap-images-2njarrj.jpg)
FILE: Roger Federer of Switzerland reacts after winning the men's single final against Rafael Nadal of Spain at the Australian Open tennis tournament in Melbourne, Australia on Jan.29, 2017. Former world number
![Roger Federer of Switzerland and Rafael Nadal of Spain prepare to... Photo d'actualité - Getty Images Roger Federer of Switzerland and Rafael Nadal of Spain prepare to... Photo d'actualité - Getty Images](https://media.gettyimages.com/id/81834744/pt/foto/roger-federer-of-switzerland-and-rafael-nadal-of-spain-prepare-to-play-the-mens-singles-final.jpg?s=612x612&w=gi&k=20&c=UPcFLa510zAyFOKCi5KY_YHbZgQallBqNXixhBwDcME=)