Roger Federer has announced his intention to retire after the next tournament, becoming the second tennis superstar in recent weeks to call it quits.
Serena Williams, who retired after losing the third round of the US Open, offered kind words to Federer in a touching Instagram post.
"I have always loved and admired you," Williams wrote. "Our paths have always been the same, very similar. They have inspired countless millions and millions of people - including me - and we will never forget them."
Williams continued: "I admire you and look forward to all that you do in the future. Welcome to the retirement club. And thank you for being you."
Unlike Williams, the Swiss superstar will not end her career at the Grand Slam. Federer, who recently turned 41, announced his retirement in the Laver Cup to be held in London from September 23 to 25. He cited a recent injury as the reason for his retirement.
"As many of you know, the last three years have been challenging with injuries and surgeries," Federer said. "I've worked hard to get back to a full season. But I know my body's capabilities and limitations, and the message of this is clear to me."
One of the greatest tennis players of all time, Federer will end his career with 20 Grand Slam singles championships, third behind Rafael Nadal (22) and Novak Djokovic (21). Williams holds the all-time Open Era record with 23 singles championships.
The retirements of both Federer and Williams represent the beginning of change for tennis' next generation of stars. The US Open was won by two players early in their careers: Inga Switek won his third career title and 19-year-old Carlos Alcaraz won his first.