Coco Gauff became the youngest player to win the WTA Finals title in 20 years with a gruelling 3-6, 6-4, 7-6 (7/2) victory over Olympic champion Zheng Qinwen in Riyadh on Saturday.The doubles title in Riyadh was secured by Canadian Gabriela Dabrowski and New Zealand’s Erin Routliffe, who avenged their Wimbledon final loss to Taylor Townsend and Katerina Siniakova by defeating the American-Czech duo 7-5, 6-3.