Mladenovic was one of seven players placed under extra restrictions during the tournament after contact tracing determined she potentially could have been exposed to COVID-19 by Benoit Paire, the only entrant to test positive.
"As the players are staying in Nassau County, the quarantine notices prevent any of these individuals from commuting to the USTA Billie Jean King National Tennis Center in New York City".
Mladenovic has not been so fortunate, and a statement from tournament organisers read: "Public health officials of Nassau County, (New York), have issued quarantine notices for all individuals who had prolonged close contact to a person who previously tested positive for the COVID-19 coronavirus".More news: Tiffany Haddish Reveals She Contracted COVID-19, Interviews Dr
"The USTA is obligated to adhere to government guidance at the state, city and county level".
Babos also contrasted her treatement with the fact that France's Adrian Mannarino - one of those who had been in contact with Paire - was allowed to play against Alex Zverev in the third round on Friday. Last year's runner up in New York, Medvedev defeated Tiafoe in the first round of the Australian Open this year, but the 22-year-old is playing with a newfound gusto after tennis's months-long hiatus.
Officials from NY state's department had contacted the USTA to say that Mannarino should have been quarantining in his hotel room.
This is a step up from NY, where eight players - including world No1 Novak Djokovic - were reported to have paid astronomical sums to rent a private home with 24-hour security guards to make sure that they didn't breach pandemic protocols.
Mannarino on Friday told reporters that organizers told him that NY state authorities had taken over the case from the city and ruled that he was not allowed to play.More news: Montrezl Harrell, 6th NBA Man of the Year
The players signed an agreement with New York City authorities that allowed them to remain in the tournament under the enhanced restrictions, which involved daily testing and barred them from communal areas in their hotel.
Players movements are tightly controlled and everyone onsite is being tested regularly to minimize the risk of infection.
She had complained saying she felt like she was being treated like a prisoner after she was placed inside a "bubble within a bubble" despite "thirty negative tests".
That September 12th date is 14 days after the players played cards with Paire, who tested positive for Coronavirus. Canadian Vasek Pospisil upset eighth-seeded Roberto Bautista Agut in five sets Saturday to join him, backing up a busy time off the court with on-court results.
In the women's draw, unranked Bulgarian Tsvetana Pironkova caused her second upset of the week, knocking out 18th seed Donna Vekic in straight sets. He will face unseeded American Frances Tiafoe for a place in the quarterfinal.More news: Serena through to US Open last 16 after battle with Stephens