Serena Williams tweaked her knee during Wimbledon return at age 44 but still aims to play doubles

Serena Williams' agent says the 23-time Grand Slam champion tweaked her right knee at Wimbledon during her first singles match in nearly four years but still hopes to play doubles with sister Venus later in the week. The 44-year-old Williams did not ask for medical treatment during a 6-3, 6-7 (6), 6-3 loss to 20-year-old Maya Joint of Australia in the first round on Tuesday. Williams did not meet with media after the match.