Coco Gauff showed supreme determination to come from behind against Zheng Qinwen to win the season-ending WTA Finals.

In an enthralling encounter that lasted just over three hours, the American beat the Olympic champion 3-6 6-4 7-6 (7-2) in Saudi Arabia.

At 20 years old, she is the youngest player to win the tournament since Maria Sharapova exactly two decades ago, and the youngest American since Serena Williams in 2001.

“That was a great match, I was just trying my best to hang in there and I never gave up,” Gauff told Sky Sports.

“Sometimes you can think [you’re not going to win] but I just pushed that thought away. I was telling myself, ‘another point, another chance’.

“I’ve been in situations like this in the past where I’ve been able to turn it around and I just hoped I could do it again today.”

In progressing to Saturday’s showpiece, Gauff had become the youngest player to reach the championship match at the WTA Finals since Caroline Wozniacki in 2010.

She had not dropped a set en route, and had seen off both the world number one and two in Aryna Sabalenka and Iga Swiatek, and she piled the pressure on her opponent in the early stages against Zheng.

In what was only their second meeting – Gauff having won their first in straight sets in Rome earlier this year – Zheng, 22, was forced to save four break points, including three in an enthralling fifth game.

But it was the Chinese seventh seed who got the decisive break in the opener, a double fault from Gauff after a hat-trick of unforced errors giving Zheng the advantage and the opportunity to serve out the set.

Yet those errors looked to have had no ill-effect on Gauff as she found herself with a break back point in the next game, but squandered her opportunity before gifting Zheng the set with a backhand slammed into the net.

Zheng’s serve is one of her greatest weapons, but she struggled to show it off against Gauff, with her first of only four aces coming at the start of the second set after she had broken Gauff’s serve again.

With renewed determination, the American restored parity in an outstanding return game, after which the pair again traded breaks. But the unperturbed Gauff broke Zheng’s serve for the third successive game to take the match to a decider.

At the start of the third set, Gauff saved three break points before conceding as Zheng took back control on her serve – yet it was only temporarily.

Gauff soon broke back, her fine play at the net rewarded as Zheng sent a forehand long, before securing another love hold.

Zheng then won three successive games, dropping just four points along the way, and looked to be sauntering towards the win. But a game of errors when serving for the match brought Gauff back into contention.

That was the start of the American’s own three-game run, her spree halted as Zheng saved two championship points to ensure the tournament would be decided by a tie-break.

That was utterly dominated by Gauff, who dropped to the floor as her forehand at the net dropped into space.

Earlier on Saturday, second seeds Erin Routliffe and Gabriela Dabrowski won the doubles title in Riyadh.

The New Zealand-Canadian pair beat American Taylor Townsend and Katerina Siniakova of the Czech Republic 7-5 6-3, avenging their loss in the Wimbledon final.