British number one Johanna Konta has pulled out of the US Open, just hours before she was set to play her opening match on Monday.
The reason for world number 47 Konta's late withdrawal was unclear.
Konta, who missed Wimbledon because of a close coronavirus contact and then the Olympic Games after contracting it herself - has been managing a long-term knee injury.
It is the latest blow in a difficult year, which has also included splitting with coach Dimitri Zavialoff for a second time.
There was a huge positive earlier this month when she beat Ukraine's world number five Elina Svitolina in Montreal, but she then pulled out of her following match against American teenager Coco Gauff.