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.

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.

Yet 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.

She is the first American to win the Finals since Serena Williams in 2014, and received $4.8 million in prize money. She also is the youngest player to win it since Maria Sharapova in 2004, the year Gauff was born.

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

She felt vindicated after that and appeared to take a swipe at observers who wrote her off.

“I just love to say I’m right. Specifically today, I got comments about how I was going to lose badly, so I was just like, ‘OK, we’ll see,’” Gauff explained. “It’s honestly just liking the idea of just proving people wrong and, and letting your racket do the talking. And so, yeah, I use it as motivation.”

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.

“The match today, it’s just a couple of important points,” Zheng said. “The match was very close.”

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. They are the first players from Canada and New Zealand to win the doubles title.