Tennis legend Roger Federer wrote a heartfelt letter to Rafael Nadal on Tuesday before the Spanish star joins him in retirement. Nadal is participating in the Davis Cup in Malaga, Spain this week before saying goodbye to the sport he has played professionally since 2001.

Federer turned pro only three years before Nadal, and they spent their careers competing against each other. The rivalry developed into a friendship, and Federer's words this week were filled with nostalgia and celebration as he shared that Nadal made him "reimagine" his game.

"Let's start with the obvious: you beat me—a lot. More than I managed to beat you," wrote Federer, who trails his all-time series with Nadal, 24-16. "You challenged me in ways no one else could. On clay, it felt like I was stepping into your backyard, and you made me work harder than I ever thought I could just to hold my ground. You made me reimagine my game—even going so far as to change the size of my racquet head, hoping for any edge."

Federer listed a few of the quirky things he noticed about his rival's process and rituals. It included how Nadal likes to assemble his water bottles "like toy soldiers in formation," how he constantly fixes his hair, and adjusts his underwear.

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"I'm not a very superstitious person, but you took it to the next level.... All of it with the highest intensity," Federer wrote. "Secretly, I kind of loved the whole thing. Because it was so unique—it was so you."

Federer went on to share some of their biggest moments, such as when he was world No. 1 for the first time after the 2004 Australian Open -- only for Nadal to walk on the Miami court two months later with his "red sleeveless shirt, showing off those biceps" and beating him convincingly. 

"We were both at the start of our journey and it's one we ended up taking together," Federer said. "Twenty years later, Rafa, I have to say: What an incredible run you've had. Including 14 French Opens—historic! You made Spain proud... you made the whole tennis world proud."

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Federer also has not forgotten how Nadal was by his side, quite literally, during his own retirement at the 2022 Laver Cup in London. That event gave us the iconic photo in which they are holding hands with tears in their eyes -- which spoke not just about their legendary rivalry, but also the depth of their friendship. According to El País, Federer has that photo framed in his home.

"It meant everything to me that you were there by my side—not as my rival but as my doubles partner," Federer wrote. "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, who all played a massive role in your success. And 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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