World number two Ashleigh Barty suffered a shock defeat in the fourth round of the US Open.
The Australian, who won the French Open earlier this year, was beaten in straight sets by Wang Qiang, the 18th seed from China.
Below-par Barty was broken twice in the first set and saved two match points on serve in the second.
She had a chance to break back but the hugely impressive Wang, playing in the fourth round of a grand slam for the first time, held her nerve.
A fourth match point saw the 27-year-old over the line and into the quarter-finals.
"'Q' was very good, very solid," said Barty. "I felt like she was able to put the ball with great depth in difficult positions for me.
"I still was able to create opportunities, it was just very frustrating that on the big points today, she played a lot better.
"I mean I had nine break points, and I wasn't able to even get one of them, which is really frustrating.
"But it's been a great season in grand slams, making the second week in every single one, which has been really special.
"Now we'll sit back, reflect, and look forward to a big couple months to finish off the year."
Johanna Konta pulled off one of the biggest wins of her career by beating third seed Karolina Pliskova to reach the last eight.
The British number one dropped the first set on a tie-break but battled back to win 6-7 (1), 6-3, 7-5.
In doing so Konta became the first British woman to reach the last eight at Flushing Meadows since Jo Durie in 1983.
Konta had lost six of her previous seven matches with Pliskova, including twice on her home turf of Eastbourne, as well as in Nottingham and Birmingham.
None of those defeats will matter now with Konta continuing her fine season in the grand slams with a third successive appearance in a quarter-final.