Elina Svitolina beat Sloane Stephens to claim the biggest title of her career at the WTA Finals in Singapore.
The first Ukrainian to be crowned champion, Svitolina recovered from a difficult start to win 3-6 6-2 6-2.
Stephens, the 2017 US Open champion, controlled the first set but Svitolina broke three times in the second.
The 24-year-old then repeated the feat in the decider to become the first player to go unbeaten at the tournament since Serena Williams in 2013.
"It is amazing. I am very pleased with my performance this week," said Svitolina, who has won her past nine finals on the WTA Tour and not lost one in the last two seasons.