Madison Keys has recovered from a set down to defeat Aleksandra Krunic and reach the fourth round of the US Open.
The 14th seed reached her first grand slam final in New York 12 months ago, but looked in trouble when Krunic took the first set on Saturday.
The Serbian arrived at Flushing Meadows on a five-match losing streak and having won only four games across three matches on the North American hard courts.
She has hit form again here and played a fine first set, but Keys turned things around to win 4-6 6-1 6-2.
There was an upset on Louis Armstrong Stadium, though, as in-form Kiki Bertens fell to Czech teenager Marketa Vondrousova.
Bertens has had an excellent season and defeated Simona Halep to win the title in Cincinnati two weeks ago.
That put her among the contenders for the title in an open women’s draw, but she was unable to overcome 19-year-old Vondrousova, who won a deciding tie-break for a 7-6 (7-4) 2-6 7-6 (7-1) victory.