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.