NEW YORK: For Caroline Wozniacki, it was like "drinking a margarita on a beach" but for tearful Alize Cornet it was a "nightmare" as temperatures nudged towards the 40-degree mark at the US Open on Tuesday.
Four of eight early men's first round matches ended in retirements. Temperatures were expected to soar to 38 degrees (100 farenheit) by mid-afternoon, the effect made worse by suffocating humidity.
That may be short of the 41 degrees which remains New York's record temperature recorded in 1936 but that was little comfort for the likes of French player Cornet.
The 28-year-old described the conditions as a "nightmare" as she slumped to a three-set loss to Johanna Larsson of Sweden.
Cornet wept as she sat courtside, telling doctors that she was ready to vomit and felt pain in her head and bones.
Cornet had already been hit with a code violation for changing her shirt on the court after putting it on the wrong way round during the "heat rule" break allowed by the WTA after two sets when the temperature goes beyond 30.1 degrees.
In response to the conditions, tournament organisers have allowed the men to opt for a similar 10-minute off-court rest at two sets to one.
"The tournament referee, along with the medical team, will continue to monitor on-site conditions, to determine when the Extreme Heat Policy will no longer be in effect," said a spokesman.
That came too late for the likes of Stefano Travaglia of Italy, Argentina's Leonardo Mayer, Ricardas Berankis of Lithuania and Romania's Marius Copil who all quit their first round matches on Tuesday.
Copil had been 5-1 up in the first set on 2014 champion Marin Cilic on the Grandstand when he quit in the third set.
"The conditions were really difficult and it's tough on Marius. He really felt something," said seventh seed Cilic.
Australian Open champion and second seed Wozniacki dreamed her heat troubles away as she defeated 2011 champion Samantha Stosur 6-3, 6-2 on a sweltering Arthur Ashe Stadium.
"I just tried to cool down between games, used ice. I'm just thinking I'm on the beach, I have a margarita in hand, life is good," she said.
Two-time Wimbledon champion Petra Kvitova was just happy to finish her 6-4, 6-1 win over Yanina Wickmayer before the afternoon began to really cook.
"I was pretty lucky to play first on today, definitely. I knew it's going to be very hot, but I couldn't imagine how horrible the heat was," said the Czech.
The heat and humidity had already been an issue on Monday when Stan Wawrinka, Kevin Anderson and David Ferrer all needed medical time outs.
So did Canadian teenager Félix Auger-Aliassime who quit his match against compatriot Denis Shapovalov after a worrying increase in his heart rate.
"That wasn't easy to see," said Shapovalov. "It's tough to keep pounding at it when he's a brother to me."
The United States national weather service says its heat advisory for New York City will remain in place until Wednesday night.
"The combination of hot temperatures and high humidity will combine to create a situation in which heat illnesses are possible," said the body.