Top seed Karolina Pliskova made a confident start to her US Open campaign with a 6-4 6-0 win over Ukraine’s Anhelina Kalinina in New York.
The Czech, 28, recovered from dropping serve in the first game to later string together eight games in a row, needing just 21 minutes to take the second set.
Pliskova, top-ranked in the absence of Ashleigh Barty and Simona Halep, faces France’s Caroline Garcia next.
Also through are ex-Wimbledon champions Petra Kvitova and Angelique Kerber.
German 17th seed Kerber, playing her first match since January’s Australian Open, beat Australian Ajla Tomljanovic 6-4 6-4.
Czech sixth seed Kvitova overcame Romanian Irina-Camelia Begu 6-3 6-2, hitting 23 winners in an assured performance.
Other women in action on day one at Flushing Meadows – where the tournament is being held behind closed doors – include Japan’s 2018 champion Naomi Osaka and American teenager Coco Gauff.