Roger Federer says Rafael Nadal "made the whole tennis world proud" during his "epic career" as he paid tribute to his former rival before his retirement.

Nadal, a 22-time Grand Slam champion, will bring an end to his illustrious career aged 38 after representing Spain at the Davis Cup Finals in Malaga this week.

Federer, who retired in 2022 with 20 Grand Slams, won 16 matches and lost 24 - including an epic final at Wimbledon in 2008 - in the 40 times he faced Nadal.

"As you get ready to graduate from tennis, I've got a few things to share before I maybe get emotional," wrote 43-year-old Federer on Instagram.

"Let's start with the obvious: you beat me - a lot. More than I managed to beat you. 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."

American great Serena Williams posted on X: "Why am I getting so choked up with Rafael Nadal's retirement? I'm not good at goodbyes."

The 23-time Grand Slam singles champion also posted a video on Instagram of her wearing one of Nadal's branded headbands and a t-shirt with the Spaniard on.

"Congratulations on a career that most won't dare to dream of," she said.

"I feel so fortunate to have been able to play when you were playing and being great.

"Your legacy will never die. To see your career from the beginning to today was an honour. Long live Rafa!"

Federer said that Nadal made him "reimagine" his game, to the extent that the Swiss changed the size of his racquet head.

A 37-year-old Federer triumphed in the pair's final encounter, in 2019 at Wimbledon, but it was a 17-year-old Nadal who won their first meeting, in 2004.

"I thought I was on top of the world. And I was - until two months later, when you walked on the court in Miami in your red sleeveless shirt, showing off those biceps, and you beat me convincingly.

"All that buzz I'd been hearing about you about this amazing young player from Mallorca, a generational talent, probably going to win a major someday - it wasn't just hype.

"We were both at the start of our journey and it's one we ended up taking together. 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."

Federer teamed up with Nadal for the final match of his career when the pair - affectionately nicknamed 'Fedal' - played together in the doubles for Europe against the Rest of the World at the Laver Cup.

Both players were in tears as Federer bowed out of the game.

"Sharing the court with you that night, and sharing those tears, will forever be one of the most special moments of my career."

He added: "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."

Women's world number two Iga Swiatek said on X that watching Nadal become emotional during the national anthem before his loss to Botic Van de Zandschulp on Tuesday was "too much".

Aryna Sabalenka, the top-ranked women's player, also wore Nadal's branded clothing in a photo on Instagram.

In Paris, the city where Nadal won a record 14 French Open men's singles titles, images of the Spaniard were projected into the night sky at the Trocadero against the backdrop of the Eiffel Tower.