Angelique Kerber, Petra Kvitova, Caroline Garcia and Jelena Ostapenko were among the seeded women to overcome the stifling conditions to win through to the second round of the US Open.
German fourth seed Kerber was pushed to a tiebreaker in the first set in a 7-6 (7-5) 6-3 victory over Russian Margarita Gasparyan.
With the temperature pushing toward 100 degrees fahrenheit (38C) during play on Tuesday, Kerber was relieved to wrap up the match in straight sets.
“It was really not easy out there today,” she said. “I think it’s one of the hottest days that I remember here.
“But at the end, when you’re out there, you just try to survive a little bit.”
Fifth-seeded Kvitova took just one hour and 12 minutes to seal a 6-1 6-4 victory over Yanina Wickmayer.
The Czech is famously not a fan of extreme heat and has struggled in New York in the past, although she has made the quarter-finals in two of the past three years.
“I knew it’s going to be very hot but I couldn’t imagine how horrible the heat was, so it was pretty difficult conditions,” she said.
“But I just felt good from the beginning when I played a really good game. I really tried hard not to play a third (set).
Garcia also made light work of her opening round match with a comfortable 6-2 6-2 win over England’s Johanna Konta.
The French sixth seed progresses to face Puerto Rican Monica Puig, who matched Australian Daria Gavrilova’s Monday feat of a “double bagel” in dispatching Switzerland’s Stefanie Voegele 6-0 6-0.
Latvian 10th seed Ostapenko sweated out a 6-4 4-6 7-5 win over German Andrea Petkovic, ending the two hour and 18 minutes slugfest on her fourth match point.
Other seeded players to advance to the second round included 11th-seeded Russian Daria Kasaktina, Dutch 13th seed Kiki Bertens and Japan’s 20th seed Naomi Osaka.
American 24th seed CoCo Vandeweghe crashed out 6-2 7-6 (7-3) to Kirsten Flipkens of Belgium while Canadian qualifier Eugenie Bouchard won a match at the US Open for the first time since 2015 – the year she withdrew from the tournament after a fall left her with a concussion.