Former World No.1 Caroline Wozniacki notched the first Top 20 win of her comeback on Wednesday, upsetting No.11 seed Petra Kvitova 7-5, 7-6(5) in a US Open second-round showdown between Grand Slam champions.

Wozniacki, the US Open runner-up in 2009 and 2014, needed 2 hours and 8 minutes to take down Kvitova. Wozniacki advances to a third-round clash with another player on the comeback trail, former Australian Open finalist Jennifer Brady of the United States.

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The winner speaks: "It feels amazing to beat such an amazing player and champion like Petra," Wozniacki said, after her win.

"Obviously I knew coming into the match that I had a chance to win, and I believe in myself. At the same time she obviously has had a great year. She's 11 in the world, loves to play on hard courts. I knew it was going to be a very tough one and I had to play my best tennis."

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Return surging: Denmark’s Wozniacki came back to WTA action just three weeks ago in Montreal, after a three-and-a-half-year hiatus. During that time away, the 2018 Australian Open champion gave birth to children Olivia and James.

Wozniacki posted a 1-2 win-loss record over her three matches at Montreal and Cincinnati. But now, Wozniacki finds herself back in the third round of a Grand Slam, having already beaten qualifier Tatiana Prozorova in this week's opening round.

Fast facts: This is Wozniacki’s first Grand Slam event since she lost in the third round of the 2020 Australian Open to Ons Jabeur. That defeat was the last match Wozniacki played before her return this month.

Prior to Wednesday's victory, Wozniacki’s most recent Top 20 win came over Kvitova as well, when she beat the Czech at the 2018 WTA Finals nearly five years ago. 

Wednesday's result marks Wozniacki's 40th career match-win at the US Open. She is the first player from Denmark, female or male, to amass 40 career wins at the US Open in the Open Era (since 1968).

Rivalry renewed: Wednesday's match was the latest in an extended rivalry between Wozniacki and Kvitova which dates back to 2009. Kvitova still holds an 8-7 lead in their head-to-head, but this time around, Wozniacki got the better of this year’s WTA 1000 Miami champion.

On Wednesday, Kvitova had 38 winners to Wozniacki's 22, but Wozniacki played the tidier match. Wozniacki only hit 13 unforced errors, while former World No.2 Kvitova tripled that number with 39.

In the back-and-forth first set, Wozniacki took a 6-5 lead by holding with two consecutive aces. In the next game, Wozniacki hit a sturdy service return on her second set point, forcing an error and ending the opening frame after 63 minutes.

Kvitova saved two match points at 5-4 in the second set before the players moved into a tiebreak. In the breaker, a return winner gave Wozniacki a commanding 4-1 lead, and she held on from there, closing out the match after a long return by Kvitova.

Comeback vs. comeback: Wozniacki will now have her first meeting with Brady, who outlasted No.24 seed Magda Linette 6-1, 2-6, 6-2 on Wednesday night. Former World No.13 Brady also came back to tour just this summer, having missed two years of play due to persistent injuries.