Play on the outside courts at the US Open has been suspended after a tornado warning was issued for New York.
Even on the mostly covered Louis Armstrong court, fans were forced to take cover as rain entered through gaps in the stadium roof.
Many opened umbrellas and donned ponchos amid the wild conditions.
Play in the match between Diego Schwartzman and Kevin Anderson was suspended as rain made its way onto the court — despite the roof.
“The region is currently under a tornado watch with potential for lightning,” the US Open said.
“We are tracking the conditions and will provide further updates as needed.
“We encourage everyone to exercise caution when travelling.”
On the other covered show court, Arthur Ashe, rain could clearly be heard hammering onto the roof during the match between Adrian Mannarino and Stefanos Tsitsipas.
Alexei Popyrin stuns Grigor Dimitrov
Earlier in the day, Australia’s Alexei Popyrin recorded one of the biggest wins of his young career, with a straight-sets victory over 15th-seeded Bulgarian Grigor Dimitrov at the US Open.
Popyrin came back from a break down in both the first and second sets and was up a double break in the third before Dimitrov, who had previously called the trainer for a foot injury, retired hurt.
The 22-year-old Australian advanced to the third round with a 7-6 (7/4), 7-6 (7/4), 4-0 (ret) victory.
While Dimitrov’s retirement may have taken some of the gloss off the victory, it was a performance Popyrin could be proud of, similar in quality to his 2019 victory over future US Open champion Dominic Thiem at Melbourne Park.
The Australian took the game to the experienced Bulgarian throughout by attacking the net and playing an all-court style which saw him dominate off the backhand swing.
Frequently the Australian came out on top of crosscourt rallies as his heavy backhand forced Dimitrov into plenty of errors off his, often considered his more dangerous side.
“It was a high-level match. He’s a really tough opponent to play but we came out with the right tactics and implemented them really well,” Popyrin said.
“He countered them quite well as well, so I had to figure out a way in the first set how to get back from a break down.
“I’m just happy I was able to maintain that level over the course of the first two sets, and then unfortunately he had to retire.”
It was Popyrin’s fourth victory over a player in the world’s top 20, but three of them have come this year.
The victory means he will play 24th-seeded Briton Dan Evans in the third round.
The winner of that match will likely face number two seed Daniil Medvedev in the round of 16.
Osaka through as weather plays havoc on outside courts
Defending champion Naomi Osaka also benefited from the withdrawal of her opponent, advancing to the third round when Olga Danilović withdrew because of illness.
Simona Halep and Garbiñe Muguruza also reached the third round, ending long stretches without success in Flushing Meadows for the two-time grand slam champions.
They were among the few players to squeeze in victories early on a rainy afternoon, when play started late and then was suspended briefly on the outer courts.
Halep won 6-3, 6-1 to reach the third round for the first time since a quarter-finals appearance in 2016.
She was knocked out in the first round in both 2017 and 2018 — the latter the first time the number one seed lost in the first round of the US Open.
But she has made a strong return after missing the French Open and Wimbledon with a calf injury.
“Already it’s a better result than when I was healthy, so it’s a good thing to be in the third round here,” she joked.
The ninth-seeded Muguruza got past the second round of the US Open for the first time since 2017, beating Andrea Petkovic 6-4, 6-2.
She will play three-time US Open runner-up Victoria Azarenka. The number 18 seed beat Jasmine Paolini 6-3, 7-6 (7/1).
“I think it’s going to be a very difficult match. I think she always plays great here,” Muguruza said.
Halep and Muguruza — who have won the French Open and Wimbledon — played two of the only matches to start on time on a day when heavy rain was expected in the New York area.
Puddles filled the grounds around the Billie Jean King National Tennis Center, though rain had stopped as fans began to enter for the day session.
The outside courts were empty while they were being dried so play could eventually start.
Once they did, fifth-seeded Elina Svitolina beat Rebeka Masarova 6-2, 7-5, and number 20-seeded Ons Jabeur raced to a 6-0, 6-1 victory over Maria Camila Osorio Serrano in 53 minutes.
Most other players on the outer courts had to wait out another delay during their matches, as fans raced for cover when rain returned.
After missing Wimbledon during a mental health break, Osaka had returned to the majors with a 6-4, 6-1 victory over Marie Bouzkova on Monday night.
The two-time US Open champion hasn’t lost a Grand Slam match since Coco Gauff beat her at the 2020 Australian Open.
Danilović wrote on Instagram that she was dealing with a viral illness unrelated to COVID-19.