She was so quick, so consistent, so cool under all the pressure. Throughout her U.S. Open final match on Saturday, American Coco Gauff withstood the screams and grunts and sizzling shots of her opponent, Aryna Sabalenka, this year’s Australian Open champion, who is set to become the top-ranked women’s tennis player in the world. After a shaky first set, Gauff seemed to chase every Sabalenka effort down and send it back to her. Gauff, somehow, stopped making mistakes. She played flawlessly.

And Coco Gauff declared herself, without much debate, the future of American tennis.

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Gauff, 19, defeated Sabalenka in three sets, 2-6, 6-3, 6-2, to win the 2023 U.S. Open and become the youngest American major winner since Serena Williams won her first, the 1999 U.S. Open, at 17. After she dropped the first set, Gauff took a bathroom break—"I was nervous," she said at a press conference after the match—put some water on her face, and told herself to reset. The match turned in the second set, after Sabalenka double–faulted to give Gauff her first break of serve. Gauff went up 3-1, Gauff got sharper, and Sabalenka continued to pummel shots into the net. At 5-3, a Gauff point at the net sent the crowd into hysterics; Sabalenka sent set point long, another unforced error for the Belarusian. Onto the third.

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Gauff raised her game from the start of the decisive stanza. At her second break point of the first game, Gauff got to everything, including a Sabalenka shot that hit the chord and bounced in front of the net. After smashing a forehand winner to break Sabalenka’s serve, Gauff seemed to break Sabalenka’s will. 

Sabalenka ultimately found her serve; thanks to a pair of aces, she finally held at 4-1. But it was a bit too late. She broke Gauff to get to 4-2, but Gauff stayed steady on Sabalenka’s serve. Sabalenka couldn’t push her screaming shots past her unflappable opponent. She again gave into error, double faulting: another Gauff smash gave her a 5-2 lead.

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On match point, Gauff hit a passing shot past Sabalenka and fell to the ground. She stood and sobbed. She went into the stands to share an emotional group hug with her father Corey, the college-basketball player who learned how to coach tennis—pretty well, it turns out—and her mother Candi, the educator who helped homeschool Gauff as she pursued tennis. 

Ever since Gauff burst onto the sports scene at Wimbledon four years ago, she’s struggled with expectations thrust upon her. When she was just 15 that summer of 2019, Gauff defeated her idol, Venus Williams, and became the youngest woman to reach the fourth round of Wimbledon since Jennifer Capriati in 1991. Less than three years later, she reached the final of the French Open, facing Iga Swiatek in Roland Garros in 2022.

But she didn’t feel like she belonged. 

“Playing that match, I don't know, the whole tournament felt like a surprise to me,” Gauff said after her Thursday night semifinal win. “I was really winning and just relieved that I made it to a final because so many people expected a lot of things from me. You know, I think I just didn't really believe that I had it in me, especially at the time playing Iga, who was on a winning streak and everything.” Swiatek, who won 37 straight matches at one point last year, prevailed 6-4, 6-2.

Gauff made herself watch Swiatek lift the trophy. "I said, I'm not going to take my eyes off her, because I want to feel what that felt like for her," Gauff said Saturday night. Lifting her own trophy today "felt like craziness."

After her first-round Wimbledon ouster in July, Gauff said she started to eye 2024. “I wasn't expecting to do well honestly in this hard-court season,” Gauff said Thursday. “I was really sort of thinking for offseason and preparing for next year.” She still couldn’t shake imposter syndrome. She beat Swiatek in Cincinnati, but thought she caught her on an off day. Gauff beat Karolina Muchova in the final of the Western & Southern Open, but still totally didn’t think she deserved it.

“I felt like she wasn't physically ready to play that final,” Gauff said. “Then I told myself, I looked in the mirror, ‘I was, like, no, you're a good player, you can beat her regardless of her physical standard.’”

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“Speaking things into existence is real,” Gauff said. “I've been trying to speak more positively of myself and actually telling myself that I'm a great player.”

Gauff said at her post-win press conference that she put too much pressure on herself before that 2022 French Open final. So the night before this final, she relaxed, speaking with her boyfriend until 1 a.m. before falling asleep. But until 10 minutes before the match, she said, she was reading social media comments saying the was going to lose. It fired her up.

Since Capriati’s Australian Open victory in 2002, only three American women not named Serena or Venus Williams have won majors: Sloane Stephens at the 2017 U.S. Open, Sofia Kenin at the 2020 Australian Open and now Gauff. Video has recently been making the rounds of an 8-year-old Gauff in the stands at the 2012 U.S. Open, jumping and dancing as Carly Rae Jepsen’s “Call Me Maybe” blares over the speaker. Now that little girl is a U.S. Open champ, being handed a $3 million winner’s check.

After her win, Gauff said this was the first time she’d ever seen her father cry. She thanked doubters for fueling her fire. And she chastised her younger brother for doing a very younger-brother thing: he didn’t pick up her FaceTime call after she won the U.S. Open title. 

She’s still a kid. And now a Grand Slam champ.

The original version of this story misstated the number of American women’s Grand Slam winners—aside from Serena and Venus Williams—since 2002. It was three, not two. Sofia Kenin won the Australian Open in 2020.

Write to Sean Gregory at sean.gregory.com.