Only one Pan Pacific Open quarter-final was completed on Friday due to the rain in Osaka.
An ankle scare marked Serena Williams' fourth-round win at the US Open, where Ashleigh Barty and Karolina Pliskova were beaten.
Third seed Karolina Pliskova needed three sets to reach the fourth round but Serena Williams was dominant in progressing to the last 16.
Only five women's singles matches were completed at Flushing Meadows, where poor weather conditions prevented play outside.
Serena and Venus Williams lost three games between them as the American pair cruised through to the second round at Flushing Meadows.
Despite being a break down in both sets, Madison Keys beat Svetlana Kuznetsova to win the Western & Southern Open final.
Svetlana Kuznetsova demolished world number two Ashleigh Barty at the Western & Southern Open and will face Madison Keys in the final.
Naomi Osaka's latest reign as world number one looks to be a short one, with Ashleigh Barty close to dethroning the Japanese.
Naomi Osaka and Ashleigh Barty won through as Madison Keys overcame Simona Halep at the Western & Southern Open.
It was a good day for the seeds at the Western & Southern Open as Naomi Osaka, Simona Halep and Ashleigh Barty advanced.