NEW YORK — Coco Gauff turned the tide after trailing by a set to defeat Elina Svitolina 3-6, 6-3, 6-3 in the third round of the US Open on Friday, extending the 20-year-old American’s defense of her first Grand Slam title.

Third-seeded Gauff made one mistake after another in the first set at Arthur Ashe Stadium and lost the last 11 points against 27th-seeded Svitolina, who has reached the semi-finals of a major tournament three times.

“She’s a fighter,” Gauff said. “I knew I had to play my best.”

But Gauff won nine of 11 games in one go, despite losing the opening set, and did so three more times on her way to winning the US Open trophy in 2023, including in the final against Aryna Sabalenka.

The secret this time? “I tried to be more aggressive with my forehand,” Gauff said, “and tried to make fewer mistakes with my backhand.”

Since her Grand Slam debut in 2019, Gauff has won 12 major matches after dropping the first set, ranking her second only to Ons Jabeur (13) in that period.

The comeback ends Gauff’s five-match losing streak against top-50 opponents and may be just what she needs to overcome her recent slump, which has seen her win just five of her previous nine matches.

What a contrast to a year ago, when Gauff won 18 of 19 matches, 12 in a row, and collected two exhibition hard-court titles along the way. She also won the US Open championship, becoming the first American teenager to triumph at Flushing Meadows since Serena Williams in 1999.

On Sunday, Gauff will play for a spot in the quarterfinals, which will take place against the winner of Friday’s late match between No. 13 Emma Navarro of the United States — whom Gauff defeated in the fourth round of Wimbledon last month — and No. 19 Marta Kostyuk of Ukraine.

Everything began to change for Gauff on Friday at the 1 hour and 10 minute mark, when Gauff broke out to lead 4-2 in the second set by hitting a cross-court forehand winner. She celebrated with a shout of “Come on!” and raised her left hand to wiggle her fingers and ask the crowd to get louder.

The set was soon in the hands of Gauff, who closed the set with a 94 mph ace, shaking his fist and shouting.

In the third period, with UConn basketball stars Paige Bueckers and Azzi Fudd in her guest box in Ashe, Gauff broke through immediately, then took a 2-0 lead with the help of one point on 38 shots when Svitolina hit a backhand wide.

Gauff quickly led 5-1, whose only late wobble came when she was serving for the match at 5-2. She squandered three match points and was broken there. But Gauff broke right back to seal the match.

Gauff became the sixth American woman to win 60 major matches before her 21st birthday, following Serena Williams, Mary Joe Fernandez, Chris Evert, Venus Williams and Tracy Austin.

ESPN Stats & Information and The Associated Press contributed to this report.