What started as a rocky night turned into a gritty win and ticket to the Round of 16 at the U.S. Open for No. 6 Coco Gauff.

On Friday night under the Arthur Ashe Stadium lights, the American battled Belgium’s Elise Mertens to win 3-6, 6-3, 6-0. 

The pair had met twice previously, most recently in the fourth round of the 2022 French Open, where Gauff won in straight sets — 6-4, 6-0.

Prior to the match, Gauff noted their previous meeting as “not easy” in an interview with ESPN.

The third wasn’t any different.

In the first set, Gauff looked off, netting balls more than usual and playing up at the net, which has served her well in the previous two matches.

But Mertens was successful at lofting the ball up in bounds behind her.

Gauff then found her groove in the second set, completely shifting the momentum, and dominated in the final set in which Mertens failed to win a single game.

The 19-year-old delivered in front of a star-studded crowd that included Hailey and Justin Beiber, Michael Imperioli of “The White Lotus,” and “The Sopranos,” Heat star Jimmy Butler, and three-time Grand Slam doubles champion Jack Sock, who is Gauff’s mixed double’s partner.