Germany’s Angelique Kerber progressed to the second round of the US Open on Monday, while there were also wins for Chinese pair Duan Yingying and Wang Yafan early on day one.
Kerber, seeded second in the women’s draw and the reigning Australian Open champion, led Polona Hercog 6-0 1-0 when the Slovenian succumbed to leg cramps.
Duan had a tough three-set battle with Greece’s Maria Sakkari before triumphing 6-4 4-6 6-3, while Wang saw off Belgium’s Alison Van Uytvanck 6-3 7-6.
Third seed Garbine Muguruza came had to come from a set behind to eliminate Elise Mertens 2-6 6-0 6-3, while Carolina Wozniacki won her first Grand Slam match of 2016 with a 4-6 6-3 6-4 win over qualifier Taylor Townsend.
The former world number one had suffered first-round exits at the Australian Open and Wimbledon, and missed the French Open through injury, so will be relieved to have made it through.
Elsewhere, there were also wins for Roberta Vinci, who saw off Anna-Lena Friedsam 6-2 6-4, Petra Kvitova, who beat Jelena Ostapenko 7-5 6-3, while 24th seed Belinda Bencic eliminated Samantha Crawford with a 6-7 6-3 6-4 victory.