CHICAGO — 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.

This news comes just days after the end of the U.S. Open, which was expected to be the last tournament of 23-time major champion Serena Williams’ career.