Roger Federer has paid tribute to Rafael Nadal on the eve of the latter's retirement, saying that their rivalry "made me enjoy the game even more".
The Spaniard will end a glittering professional tennis career when he completes duty at the Davis Cup with his country this month, chasing a fifth title.
It would be a fitting final prize for the 22-time Grand Slam champion, one of the most decorated players in the sport alongside Federer and Novak Djokovic.
The three men, alongside the recently retired Andy Murray, were close competitors on the court and respectful friends off it during a golden era for the sport.
The four teamed up for Federer's final tournament, at the 2022 Laver Cup, and Nadal partnered the Swiss star in his last professional match as a doubles team.
Now, as Nadal prepares to call it quits for good following the Scotsman's retirement earlier this year, Federer has posted an emotional open letter to the star.
"As you get ready to graduate from tennis, I've got a few things to share before I maybe get emotional," the 43-year-old penned on Instagram.
"You challenged me in ways no-one else could. You made Spain proud... you made the whole tennis world proud.
"Sharing the court with you that night, and sharing those tears, will forever be one of the most special moments of my career.
"Rafa, I know you're focused on the last stretch of your epic career. We will talk when it's done. For now, I just want to congratulate your family and team.
"I want you to know that your old friend is always cheering for you, and will be cheering just as loud for everything you do next."
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