NEW YORK, NEW YORK – SEPTEMBER 01: Naomi Osaka of Japan reacts against Coco Gauff of the United States during their Women’s Singles Fourth Round match on Day Nine of the 2025 US Open at USTA Billie Jean King National Tennis Center on September 1, 2025 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Sarah Stier/Getty Images)
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Naomi Osaka views Coco Gauff as her “little sister” and on Monday big sister taught the youngster a lesson.
Playing her biggest match since becoming a mother two years ago, No. 23 Osaka started the match with great intensity and maintained dominant form while out-playing No. 3 Gauff, 6-3, 6-2 in 64 minutes before a capacity crowd in Arthur Ashe Stadium to advance to the US Open quarterfinals. By ranking, it was Osaka’s biggest win in a major.
“I was in the stands two months after I gave birth to my daughter watching Coco [in 2023],” Osaka said on court. “I just really wanted an opportunity to come out here and play. This is my favorite court in the world and this means so much to me to be back here.”
Osaka is a four-time major champion, but her last Grand Slam title came at the Australian Open in 2021 and her last US Open crown was in 2020. Her daughter, Shai, was born in 2023.
Osaka will next face No. 11 Karolina Muchova, a two-time US Open semifinalist who beat No. 27 Marta Kostyuk in three sets. The pair have split their four career matches.
Osaka will earn $660,000 for reaching the quarterfinals, and would make $1,260,000 for making the semis. The winner takes home $5 million.
“To be such an amazing role model at such a young age is a gift and I have all the respect in the world for her,” Osaka, 27, said of Gauff, 21.
NEW YORK, NEW YORK – SEPTEMBER 01: Coco Gauff of the United States reacts against Naomi Osaka of Japan during their Women’s Singles Fourth Round match on Day Nine of the 2025 US Open at USTA Billie Jean King National Tennis Center on September 1, 2025 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Sarah Stier/Getty Images)
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Gauff is a two-time major champion, having won Roland Garros earlier this year and the US Open in 2023, but she is now just 7-5 since the French Open. She replaced her coach ahead of the Open and replaced him with biomechanics expert Gavin MacMillan in order to improve her serve.
Still, Gauff struggled in the first set and double-faulted on set point. She committed 11 unforced errors and 16 total unforced errors in the first set.
For the match, she committed 33 unforced errors against 8 winners. She double-faulted 5 times against 3 aces.
“She’s guiding the ball, she’s not hitting with conviction or authority,” 18-time major champion Chrissie Evert said on ESPN.
Said Gauff: “It’s been a tough post-French Open for me for sure. I know the improvements that I need to make, and I feel like I’m making the right decision by making them. I wish I had more time between this tournament and Cincinnati, but that’s the cards that I was given.
“I think today when I walked on the court, I feel like I put so much pressure on myself at my age at 21, and I realize how much the girls on tour are being successful at 25, 26, at those ages. For me it just gets me excited to realize if I have four more years of just working as hard as I am right now and actually doing the right things, like where my game could be.”
Osaka countered with 12 unforced errors against 10 winners and 3 aces with no double faults.
NEW YORK, NEW YORK – SEPTEMBER 01: Naomi Osaka of Japan returns a shot against Coco Gauff of the United States during their Women’s Singles Fourth Round match on Day Nine of the 2025 US Open at USTA Billie Jean King National Tennis Center on September 1, 2025 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Sarah Stier/Getty Images)
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Coming into the match, Osaka pleaded with fans to root for her against the American.
“I hope, can somebody come to the match and choose for me because, I mean it’s kind of tough playing an American here, but I hope you guys kind of adopted me as well,” she said Saturday.
The fans were muted, hoping Gauff could make a match of it, but she was never able to get the crowd into the match.
Asked about the fan support after the match, Osaka said: “I was super locked in, to be honest. I was really locked in and I felt like everyone wanted to watch a really great match and that’s what you got.”
As for Gauff, she said, “I think there’s a lot of positives to take from this tournament, and I’m trying to be positive in front of you guys. I promise you that…I am not going to let this crush me.
“I look forward to the future and making more improvements. Yeah, hopefully next year I can grow a lot as a player and as a person.”