American teenager Coco Gauff qualified for the third round of the US Open on Wednesday after beating 16-year-old Russian Mirra Andreeva 6-3, 6-2.

Sixth seed Gauff, one of the favourites for the title after recent tournament wins in Washington and Cincinnati, will meet Belgium's Elise Mertens or countrywoman Danielle Collins for a place in the last 16.

After a tough opening round against German veteran Laura Siegemund, Gauff dominated the youngest player in the draw to notch a 13th win in 14 matches since losing in the Wimbledon first round.

The 19-year-old defeated Andreeva for the second time in three Grand Slams after winning their French Open clash in the first act of a potentially era-defining rivalry.

"I just learned to be aggressive, because if you give her something she is going to take advantage," said Gauff, who was taken to three sets by Andreeva at Roland Garros in June.

"I did well today making her play off her back foot.

"She has a great future in front of her - I think she is going to be back on this stage many more times."

WOZNIACKI'S US OPEN RETURN CONTINUES WITH KVITOVA UPSET

Caroline Wozniacki claimed the biggest win of her comeback and a spot in the third round of the US Open on Wednesday as the Dane's Grand Slam adventure continued with an 7-5 7-6(5) upset of 11th seed Petra Kvitova.

Twice a finalist at Flushing Meadows, Wozniacki was back on the stage she has graced so many times against a familiar foe in front of an adoring crowd under the Arthur Ashe Stadium lights.

Having retired in 2020 to raise a family and playing in just her third event since returning to action Wozniacki turned back the clock to come out on top in the battle of 33-year-old Grand Slam champions.

The last time Wozniacki beat a top 20 ranked opponent was at the 2018 WTA Finals when she took down then world No 5 Kvitova.

Five years later, their 15th meeting ended with the same outcome.

The match did not start well for Wozniacki as Kvitova broke her to open the contest. But the Dane hit back immediately with a break of her own and then clinched the first set with another break.

Kvitova was never going to outwork the Dane, who endeared herself to New Yorkers by returning to the city to run the marathon, but the Czech had other weapons including a willingness to go for the big shot.

Wozniacki showed that she still possesses some firepower and used it to blast back-to-back aces to secure a decisive break to seal the first set.

The play remained just as tight in the second with Kvitova serving to stay in the contest at 5-5, fighting off two match points to send the set to a tie-break.

But Wozniacki would not be denied, clinching the tie-break 7-5 when the Czech's desperate forehand sailed long.