CNN
 — 

Coco Gauff stunned world No. 1 Aryna Sabalenka in the semifinals of the WTA Finals on Friday, becoming the youngest player since 2010 to reach the final of the tournament.

The 20-year-old American eventually came out on top in a back-and-forth match to defeat Sabalenka 7-6 (4) 6-3 in Riyadh, Saudi Arabia, twice fighting back after finding herself a break down in the first set.

She will now face China’s Zheng Qinwen for the title and the chance to become the youngest player since Maria Sharapova in 2004 to win the prestigious season-ending tournament reserved for the best players in the world.

Already, Gauff has become the youngest player to defeat the reigning world No. 1 at the WTA Finals since Maria Sharapova defeated Lindsay Davenport in 2004, per the WTA.

And in a neat symmetry, Gauff and Zheng, 22, are the youngest pair to appear in the final since 2004 when a 17-year-old Sharapova defeated a 23-year-old Serena Williams.

Gauff is also the youngest player to beat the reigning world No. 1 and No. 2 at the WTA Finals since Kim Clijsters in 2002, per Opta.

“I asked (about the record) as soon as I got the match,” Gauff said, per the WTA. “I asked: ‘Was this the youngest? It has to be some kind of record.’ I asked the Sky team, what was the answer. They didn’t have it, but that’s good to know.

“It was 2004. The year I was born was the last time, so in my lifetime, basically, I’ve never seen it. That’s pretty cool. It just shows age is a number both ways, old and young.”

Sabalenka broke her early in the first set but the American returned the favor immediately, before Sabalenka broke again at 5-5 to give herself a chance to serve for the set.

But the Belarusian, who hit several uncharacteristic unforced errors throughout the match, squandered the opportunity and Gauff went on to win the opening-set tie break.

The American then raced to a 4-1 lead in the second set and, though Sabalenka fought hard to break back twice, she wrapped up the match with her sixth break of the contest.

She will face a tough opponent next in Zheng, the newly crowned Olympic champion who has won 31 of her last 36 matches since Wimbledon.

The Chinese star defeated Wimbledon champion Barbora Krejčíková in the semifinals, becoming the youngest player to reach the final in her debut appearance at this tournament since 2011.