Daniil Medvedev was feeling the heat on Wednesday afternoon at the US Open, and it wasn’t coming from his opponent, Andrey Rublev, whom he was on his way to beating in straight sets in their quarter-final. As the sun beat down on Flushing Meadows, the players – and crowd – simmered in the oppressive humidity.

“One player is gonna die. And they’re gonna see,” said the world No 3 as he wiped the sweat from his brow.

Medvedev is known for his outspokenness but other players have been suffering in the last few days as New York is enveloped in a late summer heatwave, which has been made worse by the humidity and lack of any cooling breeze.

“I don’t feel like I’m ever bothered too much by the heat,” said the No 9 seed, Taylor Fritz, earlier in the tournament. “I feel like [when] it’s just really humid … it just drains you.”

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During Coco Gauff’s straight sets quarter-final win on Tuesday, the thermometer on Arthur Ashe rose past 90F (32C) as the humidity soared. On Wednesday, wheelchair play was delayed until the late afternoon to catch the cooler weather. The uncomfortable conditions have been a flashpoint for the tournament, and organizers have ruled they will partly close the Arthur Ashe Stadium roof when the temperature and humidity get too much. With more steamy weather expected for the rest of the week, we’ve officially reached the tongue-wagging portion of the US Open.

This has been forecast for some time. A recent Associated Press study of the average high temperatures of the four tennis slams over the past 35 years found a “dangerous” increase in recent years, citing climate change as the catalyst. In the past the Australian Open was always presented as an extreme heat outlier – players were left cramping and gasping when smoke from the 2020 bushfires affected air quality at the tournament. And while the AP study found the Australian Open’s high temperature has risen the most sharply, the US Open nonetheless checked in as hottest of the four slams by almost 3F.

Critically, the retractable roofs covering Ashe and Louis Armstrong Stadium have only been a tournament feature since 2016 and 2018, respectively – before that there was no cover from the elements. And even with their introduction, tournament officials have only been inclined to keep a lid on the show courts for rain. Then again, in the past Roger Federer and Novak Djokovic have complained about the stadiums’ lack of circulation on court when the roofs are closed. With the roof half open during her Tuesday match against Gauff, Jelena Ostapenko said she struggled to track the ball. “Half of the court was in the shadow and half was in the sun,” she said. “Some balls I didn’t really see, like, they were flying.”

Folding fans were a popular accessory on a bright Wednesday afternoon that saw temperatures peak at 94F (34C). Spectators inside Billie Jean King National Tennis Center collected around tree-shaded courtyards and followed paths overshadowed by the stadium courts. At times during Wednesday’s match, Medvedev puffed on an inhaler to help his breathing.

“The thing is I don’t think it worked because I kind of don’t know how to use it,” he said before the match. “I really have troubles breathing, so now I’m not going to joke about it like two days or four days ago. I’m going to use it.”

Since 1988, the US Open alone has been responsible for more than half of the 17 occasions in which at least 10 players retired early because of the heat. The 2018 edition saw six players pull out of the men’s draw on day two. At one point during her opening round match that year, France’s Alizé Cornet told the on-court doctor that she needed to vomit and felt pain in her head and bones. (“A nightmare” was how she described the conditions that year.) In 1997, when court surface temperatures jumped to 130F (54C), players feared their sneakers would melt. They weren’t joking.

Over the years players have adopted various approaches to beat the heat, usually taking on plenty of water and ice between play. In his Tuesday night quarter-final against compatriot Frances Tiafoe, Ben Shelton ran a portable air conditioning contraption over his shirtless torso during one changeover. Later on, he characterized the heat and humidity in the match as a gruelling test which, coming from a Floridian, is quite something.

“You have Frances Tiafoe on the other side of the court, and you have the weather that you had in there,” said Shelton, whose game was forged at the University of Florida, where he’d learn to manage the heat. “It was pretty muggy, pretty hot. Seventy-five percent of the match, I think, both of us were finishing points fairly tired, trying to catch our breath.”

Judging by the weather forecast, the best chance for Shelton and the other players remaining in the draw is to keep a cool head.