World Number One Serena Williams is out of the Hopman Cup in Perth, Australia due to a knee injury. She was due to play her first official match for the U.S. team but pulled out after her knee became inflamed during a morning warm-up session. Williams was using the event as preparation for her 22nd grand slam singles title campaign at the Australian Open later this month. She will be replaced in the U.S. team by 20-year-old Vicky Duval.

Gauff outruns Pegula to win thriller at WTA Finals
Fermin double gives LaLiga leaders Barca win at Atletico
Manchester United rescue dramatic 4-4 draw with Aston Villa
Norris wins in Brazil as Mercedes take constructors' title
Arwa Ali wins 100m silver for UAE at Dakar Youth Olympics
