NEW YORK — Coco Gauff was not aware that she’d lost five consecutive matches against opponents ranked in the top 50. She was not sure exactly how many points in a row she’d dropped – 11, it turns out – to give away the first set against Elina Svitolina in the U.S. Open’s third round on Friday.

Here, then, is what was entirely clear to Gauff at that moment: “I needed a reset.” So before the second set, the 20-year-old from Florida went to the bathroom, changed part of her outfit and splashed water on her face. Then Gauff went back onto the court and extended the defense of her first Grand Slam title by turning things around to beat the 27th-seeded Svitolina, 3-6, 6-3, 6-3.

“Felt like a new person coming out,” the third-seeded Gauff said. “I just didn’t want to leave the court with any regrets.”

After making mistake after mistake early on at Arthur Ashe Stadium, Gauff reeled off nine of 11 games in one stretch and won again despite losing the opening set, something she did three times en route to claiming the 2023 trophy at Flushing Meadows, including in the final against Aryna Sabalenka.

“It was in my mind today. It gave me a lot of confidence,” Gauff said, “just because it felt like déjà vu a little bit.”

On Sunday, Gauff will face No. 13 Emma Navarro, one of her teammates at the Paris Olympics, for a berth in the quarterfinals. Navarro eliminated Gauff in the fourth round at Wimbledon.

“I did a good job of neutralizing her serve and just playing really aggressive from the baseline and pushing back against her groundstrokes,” Navarro said about that matchup last month. “And then always getting one more ball back in the court.”

Navarro advanced with a 6-4, 4-6, 6-3 victory over No. 19 Marta Kostyuk. Meanwhile, No. 7 Zheng Qinwen vs. No. 24 Donna Vekic set up a rematch of their gold medal match at the Summer Games four weeks ago; Zheng won that one.

In an All-American third-round men’s match, No. 20 Frances Tiafoe battled past No. 13 Ben Shelton, 4-6, 7-5, 6-7 (5), 6-4, 6-3.

No. 6 Andrey Rublev and No. 9 Grigor Dimitrov will meet in the men’s fourth round after victories on Friday.

Vekic beat Gauff in the third round at the Olympics, part of Gauff’s recent drought against top-50 foes. That also was part of a recent slump that saw Gauff win just five of her previous nine matches.

It’s such a contrast to a year ago, when Gauff won 18 of 19 matches and 12 in a row on her way to two tuneup titles on hard courts and then the championship at the U.S. Open that made her the first U.S. teenager to prevail at Flushing Meadows since Serena Williams in 1999.

By the conclusion of one set against Svitolina, it seemed as if another loss might be in the offing. Gauff’s totals were 16 unforced errors – nine on backhands – and just seven winners. She put only 45% of her first serves in. She went 0 for 3 on break points. She allowed Svitolina to claim 19 of the 28 points that lasted more than four strokes.

All of those numbers got better across the last two sets as Gauff tried to be more aggressive with her forehands and more careful with her backhands. And something else changed, at the behest of her coaches: Gauff got the partisan crowd more involved.

Svitolina said afterward she was bothered by an ankle injury picked up last week.

“I feel like she started to go (for) more a little bit. But to be fair, I didn’t play the way that I wanted to play. … Then she started to be more alive,” said Svitolina, a three-time Slam semifinalist. “And, of course, the crowd was behind her.”

Everything began to change for Gauff when she broke to lead 4-2 in the second set, smacking a cross-court forehand winner. She celebrated with a yell of “Come on!” and raised her left hand to wiggle her fingers and ask the spectators to get louder.

Soon, that set belonged to Gauff, who closed it with a 94 mph ace, shook a fist and shouted.

In the third set, with UConn women’s basketball stars Paige Bueckers and Azzi Fudd sitting in her guest box, Gauff broke right away, then held to go up 2-0 with the help of one 38-stroke point that she took when Svitolina sent a backhand wide.

Soon it was 5-1 for Gauff, whose only late wobble came when she served for the match at 5-2. She wasted three match points and got broken, but broke right back to close things out.

“I’m glad that I had that match,” Gauff said, “because I think it just makes me match-tough and gets me ready, probably, for future challenges.”