World number one Ashleigh Barty pulled out of the US Open Thursday over fears about the coronavirus pandemic in a major blow for the Grand Slam, which is scheduled to start in New York on August 31.

The Australian is the biggest name so far to withdraw from the tournament, with her decision coming as the United States marked a grim milestone when its COVID-19 deaths topped 150,000.

"My team and I have decided that we won't be travelling to the US for the Western and Southern Open and the US Open this year," she said in a statement to Australian media.

"I love both events so it was a difficult decision but there are still significant risks involved due to COVID-19 and I don't feel comfortable putting my team and I in that position.

"I wish the USTA all the best for the tournaments and look forward to being back in the US next year," she added.

Her decision came despite the New York area keeping coronavirus cases at a relatively low level since spiking in March and April while areas such as Florida, Texas and California have become hotspots.

It was not unexpected, with the 24-year-old last month expressing concerns about the US Open going ahead, and she won plenty of support Thursday on social media for her "sensible" decision to give it a miss.

Ashleigh Barty
World number one Ashleigh Barty has pulled out of the US Open Photo: AFP / KARIM JAAFAR

Barty, who surged to the top of the rankings last year and has stayed there since, said she would continue to monitor the situation before deciding whether to travel to Europe to prepare for a defence of her French Open crown.

"I will make my decision on the French Open and the surrounding WTA European tournaments in the coming weeks," she said, with Roland Garros due to start on September 27.

Barty was one of several leading women players not on the entry list Wednesday for the ATP and WTA Western and Southern Open, a tune-up event for the US Open from August 20-28 in a quarantine environment without spectators at Flushing Meadows.

Others missing included world number two Simona Halep of Romania, the current Wimbledon champion, plus fifth-rated Elina Svitolina of Ukraine and last year's US Open champion, Canada's sixth-ranked Bianca Andreescu.

Whether they play the US Open remains to be seen.

In contrast, top-ranked Novak Djokovic, the reigning Wimbledon and Australian Open champion, and world number two Rafael Nadal, the current US Open champion, were among the men's entries, signalling their likely intent to play the Grand Slam.

Also on the list was Barty's fellow Australian Nick Kyrgios, who last month blasted the ATP as "selfish" for pressing ahead with plans for the US Open.

The opinionated Kyrgios has since waged a running battle on social media with some of the top names in the game who played at Djokovic's ill-fated Adria Tour tennis exhibition, blasting their "stupidity" and risky behaviour.

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