An unwavering Elina Svitolina claimed the biggest title of her career with a gritty comeback victory against Sloane Stephens at the season-ending WTA Finals in Singapore. The Ukrainian once again dug deep to triumph 3-6, 6-2, 6-2 in two hours and 23 minutes on Sunday. She is the first player to go through the WTA Finals undefeated since Serena Williams in 2013. Svitolina has been in brilliant, aggressive form in Singapore, beating defending champion Caroline Wozniacki at the group stage and Kiki Bertens in the semi-finals.