RIYADH, Saudi Arabia — Coco Gauff won the WTA Finals for the first time by rallying to beat Olympic champion Zheng Qinwen 3-6, 6-4, 7-6 (2) in the final Saturday.

The 20-year-old American came from 2-0 and 5-3 down in the final set and was two points from defeat at one stage.

But she took the set to a tiebreaker and won the first six points. Zheng threatened a comeback, but Gauff took the victory off her third match point with a forehand winner as she came into the net.

Gauff beat the world’s top two players — Aryna Sabalenka and Iga Swiatek — on her run to the final at the season-ending event.

Zheng was looking to complete a season in which she reached a grand slam final for the first time at the Australian Open and delivered China’s first Olympic tennis singles gold medal.

But Gauff edged the three-hour final which included 26 break points. Gauff also won their only previous meeting, in the Rome quarterfinals on clay in May.

Gauff beat Sabalenka at age 19 in last year’s U.S. Open final to win her only major in singles to date. She teamed with Katerina Siniakova to win the French Open doubles this year.

In the WTA doubles final, Gabriela Dabrowski of Canada and Erin Routliffe of New Zealand beat Katerina Siniakova of the Czech Republic and Taylor Townsend of the United States 7-5, 6-3.