Former world number one Angelique Kerber suffered an early exit at the US Open but Ashleigh Barty is through to the second round.
Kerber, the 2016 champion in New York, was beaten 7-5 0-6 6-4 by France’s Kristina Mladenovic.
World number two Barty battled back from a set down to beat Kazakhstan’s Zarina Diyas 1-6 6-3 6-2.
Karolina Pliskova is also through after a topsy-turvy straight-set victory over Czech compatriot Tereza Martincova.
Pliskova, who lost to Kerber in the 2016 final, beat Martincova 7-6 (8-6) 7-6 (7-3) in a match that saw 12 breaks of serve, excluding both tie-breaks.
She will play Mariam Bolkvadze in the second round while Barty will play Lauren Davis.
“I was really pleased to be able to solve this riddle,” said Barty, who made 19 unforced errors in the first set against Diyas.
German Kerber’s poor form at Grand Slams this year continued with her opening defeat by Mladenovic, having been knocked out of the Australian Open in the fourth round, the French Open in the first round and Wimbledon in the second.
Elsewhere, America’s two-time champion Venus Williams eased through with a 6-1 6-0 victory over Chinese world number 38 Saisai Zheng.
She will face Ukrainian fifth seed Elina Svitolina in round two after she defeated American Whitney Osuigwe 6-1 7-5.
