The build-up for next month's Australian Open suffered a jolt after three coronavirus infections were reported on two flights from Los Angeles and Abu Dhabi to the year's first grand slam on Saturday, forcing two weeks of hotel quarantine for 47 players and their entourages on board.
Two-time champion Victoria Azarenka and former US Open champion Sloane Stephens are reportedly among those affected.
Details have emerged that the positive case on the Abu Dhabi flight was Bianca Andreescu's coach Sylvain Bruneau.
Top 5 tweeners: Kyrgios and Thiem among stars to pull out tricks
Players not affected will be allowed up to five hours of training a day while those on the two flights cannot.
- Murray tests positive for Covid-19 days before flight to Melbourne
- Olympic gold? Wimbledon? World No 1? - Who wants what in 2021?
British number two Heather Watson was on the Abu Dhabi flight meaning she is one of those quarantining.
Uruguayan Pablo Cuevas took to Twitter to express his feelings.
"From having 5 hours of training in a bubble to this ... (strict quarantine x 15 days). I will be showing you my workouts x Instagram (inside the room)," wrote the world number 68.
Australia has agreed to accept about 1,200 players, officials and staff on 15 flights for the major sporting event that is due to begin next month.
Australian Open organisers confirmed there are no active cases of Covid-19 in the Adelaide bubble where Novak Djokovic, Rafael Nadal, Serena Williams, Simona Halep, Naomi Osaka and Dominic Thiem are.
Apart from Cuevas, Mexican player Santiago Gonzalez also confirmed being on the Los Angeles flight in a social media post.
Other players cited by local media as likely to be on the LA flight included Tennys Sandgren, who was granted special permission to travel from California late last week after testing positive for the new coronavirus, which he had previously had, and Belarus' Azarenka.
"We are communicating with everyone on this flight, and particularly the playing group whose conditions have now changed, to ensure their needs are being catered to as much as possible," said tournament director Craig Tiley.
The inbound infections came as Australia recorded one locally acquired case, as states began to relax travel bans on signs an outbreak in the northern state of Queensland has been contained.
The case, in western Sydney, is thought to be linked a known cluster in New South Wales, the most populous state, health officials said.
Australia has halved the number of returning travellers that it will accept, to lower the risk of highly infectious strains seeping into the community, as occurred at a site in Queensland two weeks ago.
Emirates Airline said Friday it would suspend flights between Dubai and Melbourne, Sydney and Brisbane by early next week until further notice.
Queensland has recorded two weeks since its latest hotel outbreak, fuelling hopes the spread has been contained. As a result, Victoria and South Australia states will reopen borders to the state by Sunday.
Australia, which logged 20 infections hotel quarantine overnight, has been one of the world's most successful nations in managing the coronavirus spread, with about 28,700 infections and 909 deaths.
Additional reporting from Reuters.
Tennis in 2020: Naomi Osaka, Iga Swiatek lead the way in unique season
Top 10 shots from women's draw: Serena and Osaka shine
'It surprises me' - Pressure got to Medvedev against Djokovic, says Toni Nadal