Karolina Pliskova, the world's third-ranked player, qualified Friday for the knockout stages of the US Open with a 6-1, 4-6, 6-4 win over Tunisia's Ons Jabeur (62). injured right knee.
After a first round loop in 26 minutes, Jabeur has brought the doctor to be put a compress before starting the second.
"She played a lot better from the second run and she scored incredible points," said Pliskova of his opponent to explain his own difficulties.
In pursuit of a first major title, the Czech will face Britain's Johanna Konta (No. 16) or China's Shuai Zhang (No. 33) for a spot in the quarter-finals.
Pliskova, finalist in 2016, can become No. 1 in the world after the tournament.
American Serena Williams and Australia's Ashleigh Barty are also playing in their third round match.
Dabrowski and Xu advance
In women's doubles, Canada's Gabrielle Dabrowski and her Chinese partner Xu Yifan completed the first round.
They defeated Belarusian pair Lidziya Marozava and Slovenian Katarina Srebotnik in two sets of 7-5 and 6-4.
The Canadian duo of Bianca Andreescu and Sharon Fichman did not experience the same vein, losing 2-6, 3-6 to Americans Whitney Osuigwe and Taylor Townsend.