Alexander Zverev feared his tie with Adrian Mannarino may not go ahead on Friday due to Covid-19 protocols but the German secured a 6-7(4) 6-4 6-2 6-2 win in a match delayed almost three hours due to talks between organisers and New York health officials.
The US Open third-round clash was originally scheduled to start at 2.30 p.m. local time on Louis Armstrong Stadium but was pushed back while the United States Tennis Association engaged in "collaborative dialogue" with health officials.
"I was told there is very little chance that we were going to play," Zverev said courtside after the match. "The New York State called and said he (Mannarino) shouldn't play
"So it was back and forth, back and forth ... it was political, not about us players."
Mannarino was placed under an "enhanced protocol plan" after coming in contact with fellow Frenchman Benoit Paire, who pulled out of the tournament having tested positive for Covid-19.
"I was preparing to go on court at 2.30 p.m. The tour manager came to talk to me and explained the situation that the state department of health took over the city," Mannarino told reporters.
The city allowed me to play but the state took over this decision to say I've been exposed to a positive case so I should be quarantined in my room and not be able to go on the court.
"They told me they were trying to contact some guys and see if this decision could be changed. Obviously a lot of effort has been done, they pushed the match back -- Sascha (Zverev) agreed, which is nice."
World number one Novak Djokovic, who last week launched a breakaway players' body, said the communication process was not ideal but appreciated that health decisions were not always up to the organisers in New York.
"I was communicating with his coach for a few hours actually, trying to help," he said after his third-round win. "I was speaking with ATP, trying to get more information from the tour managers.
I was also trying to get to the people that are in the highest positions in New York state through some of the contacts, trying to get to the governor of New York.
When the players finally arrived on court at 5.15 p.m., Mannarino claimed the opening set in a tiebreak as an untidy Zverev posted 26 unforced errors.
"It's also different because we were supposed to play during the warmest time of the day, with our rackets a bit tighter, prepared for the ball flying a bit more," said world number seven Zverev.
"But then we came out here and played basically a night match."
The German rediscovered his rhythm in the second set to find a way past Mannarino's serve in the 10th game, unleashing a blistering forehand winner to get to one set apiece.
With momentum on his side, Zverev converted a further five break points opportunities to book a last-16 spot for the second consecutive year in New York.
Zverev next faces Spain's Alejandro Davidovich Fokina, who defeated Britain's Cameron Norrie 7-6(2) 4-6 6-2 6-1.