Roger Federer announced Thursday that he is retiring from professional tennis at age 41 after winning 20 Grand Slam titles. Federer has not competed since Wimbledon in July 2021.

He has had a series of knee operations. Federer posted his news on Twitter, saying his farewell event will be the Laver Cup in London next week. That is a team event run by his management company.

Here's how the sporting world reacted to his retirement news via Twitter: