American teenage sensation Coco Gauff has set up a third-round showdown with defending champion Naomi Osaka at the US Open.
The 15-year-old survived a second-round thriller with Hungarian Timea Babos to win 6-2, 4-6, 6-4 at Louis Armstrong Stadium on Thursday night.
"This is just the beginning, I promise," Gauff told the crowd.
Meanwhile, unseeded American Taylor Townsend upset Wimbledon champion and No. 4 seed Simona Halep in the second round with a 2-6, 6-3, 7-6 (7-4) win.

New Zealand maintain unbeaten record against Scotland with big win
Formula One extends Sao Paulo contract to 2035
South Africa thump Italy to stay perfect in Nations Championship
Okafor secures Leeds win at home to Tottenham after red-card controversy
India beat New Zealand via DLS after rain-hit pace battle
