Canadian Bianca Andreescu has announced that she will defend her US Open title, hours after six-time winner Serena Williams confirmed she would also play.

Leading European players have expressed concern about US Tennis Association (USTA) plans to play the tournament in a bubble to minimise coronavirus risks.

“I have no doubt that the USTA has come up with the best plan to ensure our safety as we look to the return of tennis in 2020,” world number six Andreescu wrote on Twitter following Wednesday’s USTA announcement of details of the conditions under which the first post-Covid-19 Grand Slam tournament would be held.

Novak Djokovic, Rafael Nadal and Simona Halep have all said they are unlikely to play in the US Open.

The tournament will be played behind closed doors from August 31 to September 13.

Under the health protocols, players will be tested for Covid-19 before leaving for New York, upon arrival and once or twice a week during their stay.

They will be able to stay in a hotel where two double rooms will be reserved for them, or rent a house, outside Manhattan.

The number of members of their entourage who can accompany them remains to be determined.

Djokovic has said most players he had spoken to had “a rather negative view” about playing in New York, and predicted some would instead switch to the delayed clay court season instead.

Andreescu said she understood.

“The decision, I know was not made lightly and I completely support and understand every players personal opinions on the matter and their comfort level traveling near and far to compete on the world’s biggest stage.

“Returning to life as we once knew it is no longer an option,” she wrote. “But, I plan to make the most of the opportunity to get back on the court, re-connect with players and friends and hopefully bring tennis back to the millions of fans across the globe safely.”

Andreescu, who turned 20 in Tuesday, won her first Grand Slam title last year at Flushing Meadows by beating Serena Williams in the final.