Elina Svitolina emerged victorious at the winner-takes-all Tie Break Tens event at Madison Square Gardens in New York.
The Ukrainian world number four fought off the likes of Venus Williams, Coco Vandeweghe and Zhang Shuai, and lost just six of her 36 points played on her way to the tournament title.
The eight-woman competition marked the return of two tennis heavyweights, with new mother Serena Williams taking on her first singles event of 2018.
Marion Bartoli, who announced in December that she would be making a return to the women's tour, also made her comeback, four years after originally calling time on her career.
The pair came face-to-face in the first round of the event, with Williams triumphing 10-5.
But the multiple grand slam winner met her match in Zhang in the semi-finals, as the Chinese came through 13-11.
Svitolina, who powered to a 10-3 win in the final, takes home a 250,000 US dollar (£181,000) prize.
The event was the first women-only Tie Break Tens tournament in the United States.
Each head-to-head battle sees players fight it out to become the first to 10 points, with at least a two-point margin.