Caroline Wozniacki claimed the biggest win of her comeback and a spot in the third round of the US Open as the Dane's Grand Slam adventure continued with an 7-5 7-6(5) upset of 11th seed Petra Kvitova.
Twice a finalist at Flushing Meadows, Wozniacki 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 returning to action Wozniacki turned back the clock to come out on top in the battle of 33-year-old Grand Slam champions.
"I've been feeling very comfortable here in New York in general," said Wozniacki. "Ever since I arrived here, it's just something about the courts, everything else, that have made me feel good.
"I'm just so thrilled to have an opportunity to play out on Arthur Ashe Stadium.
"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."
World number one Iga Swiatek moved into the third round of the US Open, but not without a fight, taming feisty Daria Saville, who had warned she had the game to make the defending champion uncomfortable.
After a 6-0 6-1 rout of Sweden's Rebecca Peterson in her opening match, Swiatek did not look as at ease as she was made to work for a 6-3 6-4 win over the 322nd-ranked Australian spark plug.
"I just felt like I kind of prevailed, because that match wasn't easy," said Swiatek, who next meets the player she describes as her best friend on the WTA Tour Slovenian qualifier Kaja Juvan. "I'm just happy to be in the third round.
"For sure I want to improve some stuff, because I did some unforced errors.
"It's just the beginning of the tournament, so for sure I work on some stuff."
Earlier, one teenage star beat the new kid on the block as Coco Gauff knocked 16-year-old Mirra Andreeva out of the US Open.
Gauff, who burst onto the scene when she beat Venus Williams on her way to the fourth round at Wimbledon aged 15, ousted the Russian rookie 6-3 6-2.
The sixth seed, still only 19, had to come from behind to beat Laura Siegemund in a drama-filled three-setter on Monday, but she had a far more gentle workout this time on Arthur Ashe.
Gauff is fast becoming a live contender for the title this year having won 13 of her 14 matches since losing in the Wimbledon first round to fellow American Sofia Kenin.
She lost a first-set tie-break against Andreeva at this year's French Open but came back to win in three.
Gauff said: "I just learned then to be aggressive, because if you give her something she is going to take advantage.
"She has a great future in front of her – I think she is going to be back on this stage many more times."
There was another home success in New York when Taylor Townsend beat Brazilian 19th seed Beatriz Haddad Maia 7-6 (7-1) 7-5.
