It was business as usual at the U.S. Open on Wednesday with Novak Djokovic and Iga Swiatek marching confidently into the third round but the day ended with a late run of shockers that saw Casper Ruud and Petra Kvitova dumped out of the tournament.
There were plenty of cheers rolling across the sprawling Billie Jean King National Tennis Center all day with Coco Gauff, Taylor Fritz and Frances Tiafoe moving on, as hopes of a homegrown winner continued to build.
But while results followed the form book for much of the day at the year's final Grand Slam, shocks sprung up as the sun went down.
The biggest surprise was delivered by Zhang Zhizhen, who stunned last year's runner-up and world number five Ruud 6-4 5-7 6-2 0-6 6-2 to became the first Chinese man to beat a top-five player since the introduction of the ATP rankings in 1973.
At almost the same time Caroline Wozniacki was claiming the biggest win of her comeback - a 7-5 7-6(5) victory over 11th seed Kvitova.
Earlier, Swiss young gun Dominic Stricker delivered a shock by grinding out a 7-5 6-7(2) 6-7(5) 7-6(6) 6-3 win over Greek seventh seed Stefanos Tsitsipas for his first top-10 win.
Djokovic was prevented from playing in last year's U.S. Open due to being unvaccinated against COVID-19 but has looked right at home on Arthur Ashe Stadium court.
A nine-times finalist at Flushing Meadows, the Serb was in ruthless form as he rolled to a second straight dominating win, brushing aside Spain's Bernabe Zapata Miralles 6-4 6-1 6-1.
Djokovic remains on course for a fourth U.S. Open title that would pull him level with Margaret Court's record haul of 24 Grand Slams.
Swiatek has also impressed but the defending champion was made to work for a 6-3 6-4 win over Australian spark plug Daria Saville, who is fighting her way back to fitness from injury that has seen her ranking tumble to number 322.
Wozniacki, twice a finalist at Flushing Meadows, was back on the stage she has graced so many times against a familiar foe in front of an adoring crowd under the Arthur Ashe Stadium lights.
Having retired in 2020 to raise a family and playing in just her third event since her return, Wozniacki turned back the clock to come out on top in the battle of 33-year-old Grand Slam champions.
The last time Wozniacki beat a top 20 ranked player was at the 2018 WTA Finals when she took down then world number five Kvitova and their 15th career meeting ended with the same outcome.
"I'm just so thrilled to have an opportunity to play out on Arthur Ashe Stadium," said Wozniacki. "Three years ago if you'd asked me, I didn't think I was ever going to play on one of those courts again in the U.S. Open, especially a night session.
"It just feels pretty incredible to be out there and winning a match like that."
Sixth seed Gauff warmed up the home crowd early when the teenager beat Mirra Andreeva 6-3 6-3, before handing the baton to the U.S. men.
It has been 20 years and 78 Grand Slams since Andy Roddick won the 2003 U.S. Open and hopes of an American man ending that drought have fallen largely on the shoulders of Tiafoe and Fritz.
Tiafoe did not shrink under the evening spotlight, the 10th seed downing Austrian Sebastian Ofner 6-3 6-1 6-4, before ninth seeded Fritz cruised past Peru's Juan Pablo Varillas 6-1 6-2 6-2.
They were joined in the next round by Tommy Paul but only after the 14th seed battled back from two sets down to get past Russian Roman Safiullin 3-6 2-6 6-2 6-4 6-3.
Another American Ben Shelton also made it to the third round when Dominic Thiem retired with an undisclosed illness.
Thiem left the court after losing the first set tie-break but when the Austrian returned he doubled over at the net and began gagging, calling for the doctor and forfeiting the match.
