Iga Swiatek weathered an unexpected storm to reach the US Open third round on Thursday, while defending men's champion Jannik Sinner delivered a masterclass and Naomi Osaka rediscovered her groove at Flushing Meadows.
But the day's most dramatic moments belonged to Coco Gauff, who wiped away tears mid-match before rallying to beat Donna Vekic and avenge her Olympic heartbreak from Paris.
Second seed Swiatek, fresh from her Wimbledon triumph and Cincinnati title, was forced to grind it out against unseeded Suzan Lamens in a 6-1, 4-6, 6-4 thriller on Arthur Ashe Stadium that proved far trickier than expected.
"It got a bit complicated in the second set, but I'm happy that I could reset and start playing better in the third," said the 2022 champion, who sealed victory with an ace to set up a clash with 29th seed Anna Kalinskaya.
World No 1 Sinner had no such trouble, dismantling Australian Alexei Popyrin 6-3, 6-2, 6-2 in ruthless fashion to book a third-round date with Canadian 27th seed Denis Shapovalov.
Osaka, the 23rd seed, rolled past American Hailey Baptiste 6-3, 6-1 to reach the tournament's third round for the first time since 2021.
"I was just really trying to focus and not give her any free points and just be positive," said the two-time champion. "I'm really excited to be moving better."
She then weighed in on the raging debate at the tournament after Wednesday's heated on-court row between local hope Taylor Townsend and Jelena Ostapenko, condemning the Latvian for her comments toward her opponent.
The night session brought high drama as defending champion Gauff struggled with her serve against Vekic, the Croatian who had beaten her at last year's Paris Olympics.
The American has been struggling with serving problems and is trying to change her action during the tournament with the help of biomechanics expert Gavin MacMillan.
It is clearly putting a real strain on Gauff, who sat with her head in a towel after dropping serve at 4-4 in the first set of her clash with Donna Vekic, the TV cameras picking up the 21-year-old’s tear-stained face.
Gauff recovered her composure to win 7-6, 6-2 but broke down again during her post-match interview as the crowd showed their support.
“Today was a tough match for me but I’m just happy with how I was able to manage,” she said. “It’s been a rough couple of weeks. That first set was tough for me but you guys stayed cheering for me.”
Gauff also gave credit to gymnastics great Simone Biles, who was watching from the stands.
Biles overcame a mental block known as ‘twisties’ at the Tokyo Olympics, recovering to win three gold medals in Paris last summer.
“I saw her, she helped me pull it out,” said Gauff. “I was thinking, if she can go on a six-inch beam with all the pressures in the word, I can hit the ball in, I don’t even know how big this court is. It brought me a bit of calm knowing all the things she went through mentally.”
Stefanos Tsitsipas was knocked out by Germany's Daniel Altmaier in the final match of the day on the Grandstand, with the Greek 26th seed falling 7-6,1-6, 4-6, 6-3, 7-5 in a marathon that lasted well over four hours.
German third seed Alexander Zverev beat British qualifier Jacob Fearnley 6-4, 6-4, 6-4 in the first evening session match on Louis Armstrong Stadium and will next face familiar foe Felix Auger-Aliassime.
Fearnley took on the third seed for the third time this season having lost to him in Australia and Miami, and it was the same story as Zverev withstood a late salvo to claim a 6-4, 6-4, 6-4 victory.
British No 3 Fearnley revealed afterwards that Zverev had kept him waiting for more than 10 minutes before the players walked to Louis Armstrong Stadium, saying: “I kind of expected it.
“It was the same in Australia and he’s always like, ‘Oh, I’m sorry about that’. But he knows what he’s doing. It was the same with Novak [Djokovic] at Wimbledon.
“They take their time. I don’t know if it’s within the rules or not. I don’t really know what the rule is. If they call me, I show up. It is a little bit of time because you do a 20-minute warm-up and then you’re standing there.”
Two early finishes allowed organisers to move a highly-anticipated first-round doubles match involving 45-year-old Venus Williams to the second-largest stadium, where fans packed the house.
Seven-time major winner Williams, who lost in the mixed doubles and women's singles first rounds, found inspiration from Canadian partner Leylah Fernandez as they beat sixth seeds Lyudmyla Kichenok and Ellen Perez 7-6, 6-3.
"This is the best partner I've ever played with outside Serena," said Williams, who this summer became the oldest player to win a WTA singles match since 2004. "We're a great team."
Australian hope Alex de Minaur beat Japan's Shintaro Mochizuki 6-2, 6-4, 6-2, but there was bad news for his compatriot Maya Joint, who fell 7-6, 6-2 to eighth seed Amanda Anisimova in the final match on Louis Armstrong.
