Swiss tennis legend Roger Federer is to retire after next week's Laver Cup after admitting on Thursday his battles with a knee problem had forced him to call time on his historic career. "The Laver Cup next week in London will be my final ATP event," he said in a statement posted on social media. The 41-year-old winner of 20 Grand Slam titles has been out of action since a quarter-final loss at Wimbledon in 2021, after which he underwent his third knee surgery in 18 months. "The last 24 years on tour have been an incredible adventure," he wrote.