The doubles pair was stopped after Frenchwoman Mladenovic came in contact with compatriot Benoit Paire, who had to drop out of the tournament after testing positive for covid-19.

Mladenovic, one of eleven players who have come into contact with Paire, must therefore be quarantined.

"All persons who have been identified as having had prolonged close contact with the infected player must be quarantined in their rooms for the remainder of the remaining quarantine period," the US Open, which organizes the US Open, wrote in a statement referring to government decisions that the current players cannot travel back and forth between their accommodation and the competition arena.

"USTA is obliged to comply with the regulations of authorities at local, state and national level," it continues.

"Very brutal"

- It is very strange, because she (Mladenovic) was able to play in the first round of both the singles and doubles tournament and now she is suddenly kicked out, says the Frenchwoman Alize Cornet and describes the action as "very brutal".

The New York Times writes that the decision to stop the double couple was made by the health authorities in Nassau on Long Island, where the players live in a bubble.

According to the newspaper, USTA was surprised by the decision and that Nassau's authorities changed the rules for the players.

On Friday, the Frenchman Adrian Mannarino was first stopped from playing against Alexander Zverev in the third round.

That match could be played three hours after the scheduled time, then after a discussion in which, among others, Novak Djokovic participated.

World setter Djokovic resigned just before the US Open as chairman of ATP's players 'union to start his own players' organization.

Babos went home

While Mladenovic remains in his quarantine in Nassau, double partner Timea Babos has left New York.

She and coach Michael Joyce left the city on Saturday to avoid being forced into quarantine.

"This has probably cost us a grand slam title," Joyce told the New York Times before leaving.

The tennis that was played late on Saturday, local time, the two second-seeded players went on in singles.

On the women's side, the American Sofia Kenin had no problem maneuvering out Tunisia's Ons Jabeur in two straight sets.

She now meets Belgium's Elise Mertens for a place in the quarterfinals.

"Must raise the level"

In the men's tournament, however, Dominic Thiem had to fight to get to the fourth round.

The Austrian won 6–2, 6–2, 3–6, 6–3 against 2014 champion Marin Cilic from Croatia.

- I feel a little empty, but it's normal, it's really late now and there is no audience here.

But I have to raise my level if I want to go far, says Thiem after the match.

He now has to face 20-year-old Felix Auger-Aliassime, the Canadian is the first male player born in the 2000s to reach the fourth round of a grand slam tournament.