PRO TENNIS: Roger Federer says he is retiring at age 41

Roger Federer waves to spectators after defeating Daniil Medvedev in their men's singles match of the Shanghai Masters tennis tournament at Qizhong Forest Sports City Tennis Center on Oct. 10, 2018, in Shanghai, China. (AP FILE)
Roger Federer waves to spectators after defeating Daniil Medvedev in their men's singles match of the Shanghai Masters tennis tournament at Qizhong Forest Sports City Tennis Center on Oct. 10, 2018, in Shanghai, China. (AP FILE)

Roger Federer is retiring from professional tennis at age 41 after a series of knee operations, closing a career in which he won 20 Grand Slam titles, finished five seasons ranked No. 1 and helped cre…