NEW YORK, Aug 29, 2024 (BSS/AFP) - With around 55 million people placed under heat alerts, players and fans at the US Open on Wednesday struggled to keep cool as temperatures rocketed.

In the middle of the afternoon at Flushing Meadows, the searing heat reached 35 degrees Celsius (95 Fahrenheit).

"I'm sweating crazy. What was it, 95 degrees outside? Today was crazy," said American star Frances Tiafoe whose opponent Alexander Shevchenko retired in the third set of their second round clash.

Tiafoe discarded five shirts in a sweaty pile next to his chair on the Arthur Ashe Stadium.

Russia's Andrey Rublev, American teenager Iva Jovic and Victoria Azarenka all summoned doctors courtside.

Rublev, who needed five sets and more than four hours to defeat Arthur Rinderknech, told medical staff he had drank so much water that he felt he had "a baby" in his stomach.

Ukraine's Marta Kostyuk defeated Britain's Harriet Dart and spent the changeovers with an ice towel around her neck, an ice pack on her head and two wet towels under her legs.

Kostyuk even sent ice towels to her coaching staff watching from the sidelines.

Alexander Zverev, the world number four from Germany, was a straight sets winner over Alexandre Muller of France but still felt the effects of the afternoon heat and humidity.

"I was at some point very, very wet. The whole court was flooded from me, but I felt good physically," said the 2020 runner-up.

Zverev said he has developed his own routine to help combat suffocating heat.

- 'Dangerous' -

"For me, it's about getting used to the conditions before the match. I try to stay outside as much as I can," he explained.

"I try not to stay in AC, I try not to stay in rooms which are a lot colder than the playing conditions are. I spend all of my time outside."

During the day, the roofs on the two man show courts -- Arthur Ashe and Louis Armstrong stadiums were partly closed to provide desperately needed shade.

Officials also invoked the extreme heat rule which allows players to take a 10-minute break to recharge.

For men, the rule came into effect between the third and fourth sets; for women, between the second and third.

That was of little comfort to Tomas Etcheverry who vomited on court during his five-set, four-hour win against Argentine compatriot Francisco Cerundolo.

"The temperature was 38 degrees and to that we have to add another four degrees inside the court," said Etcheverry.

"You had to hydrate well, try to take as many salts and hydrates as possible and I overdid it, that's why I ended up vomiting.

"It's dangerous not only for the players, but also for the public."

Azarenka had to have her blood pressure taken in her win over Clara Burel despite playing in the evening session on Louis Armstrong Stadium.

The former world number one was reduced to tears in the match before conducting a post-match TV interview wearing sunglasses.

"I know it looks weird and awkward wearing sunglasses but I have a chronic migraine and it's really tough to deal with," she said.

As the temperatures dropped in the latter part of the evening, lightning emerged as a new threat and the clash between Casper Ruud and Gael Monfils on the uncovered Grandstand arena was suspended for safety reasons.