Sweat-drenched competitors battled through suffocating conditions as sweltering heat gripped the second-round action at the US Open on Wednesday before a lightning warning in the evening session suspended play in the outer courts.
Temperatures topped 95 degrees Fahrenheit (35°C) by the early evening as the sun beat down on the tens of thousands of fans who arrived at the sprawling Billie Jean King National Tennis Center.
Madison Keys was relieved to get past Australian qualifier Maya Joint 6-4, 6-0 in just 62 minutes at Arthur Ashe Stadium.
"I just wanted to get on and get off," the 2017 runner-up said, after she set up a meeting in the next round with Belgian Elise Mertens.
A straight-sets win was welcome for German Alexander Zverev, as he cruised past French wildcard Alexandre Muller at Louis Armstrong Stadium to set up a match with Argentine Tomas Martin Etcheverry.
"I was at some point very, very wet. The whole court was flooded from me," Zverev said. "But I felt good physically."
While high temperatures and a beating sun are nothing new at the year's final major, the conditions on Wednesday tested fans and players alike, and some athletes were not lucky enough to get a quick escape from the heat.
Etcheverry vomited amid the stifling conditions in his five-set win over compatriot Francisco Cerundolo, while Russian Andrey Rublev had to battle back from two sets down to get past Frenchman Arthur Rinderknech.
Rublev and Rinderknech wrapped themselves in ice towels during the changeovers and Rinderknech fell to the court with exhaustion after a 37-shot rally. The match was briefly halted in the second set when a spectator required medical attention.
Olympic champion Zheng Qinwen placed an ice towel around her head during her 6-7(3), 6-1, 6-2 second-round win over unseeded Erika Andreeva under the blazing sun at the Grandstand, where officials had to call a 10-minute heat break.
"Today the weather is too hot. Yeah, but all the crowd is here suffering with me from the heat," said the Chinese seventh seed, who will next play German Jule Niemeier.
Once the sun set and the temperature dipped, a lightning warning forced organisers to suspend a thriller between Casper Ruud and Gael Monfils on the Grandstand court.
While the roof was closed at Arthur Ashe Stadium and Louis Armstrong Stadium, fans at Grandstand were asked to leave for their own safety as Monfils and Ruud walked off the court.
"Play is suspended on the outdoor courts due to lightning in the area. Fans can head to Armstrong for shelter," organisers said.
