World number one Ashleigh Barty has pulled out of the US Open because of concerns over the coronavirus pandemic.
The first Grand Slam since tennis resumed is due to begin on 31 August at Flushing Meadows in New York.
The Australian, 24, was also set to play in the Western and Southern Open.
“There are still significant risks involved due to Covid-19 and I don’t feel comfortable putting my team and I in that position,” Barty told the Australian Associated Press.
“I wish the USTA all the best for the tournaments and I look forward to being back in the US next year.”
World number two Simona Halep and 2019 US Open champion Bianca Andreescu have not entered the lead-up tournament.
Barty said she will make a decision on whether to defend her title at the rescheduled French Open, which is due to begin on 27 September, “in the coming weeks”.