WIMBLEDON, England -- A wide smile spread across Naomi Osaka's face after she defeated Daria Kasatkina 6-1, 6-3 on Friday.
After only 65 minutes of play, and just over one month after advancing to the second week at Roland Garros for the first time in her career, No. 14-ranked Osaka reached the milestone at the All England Club.
The look on her face said it all: Finally.
Despite four major hard-court titles in her career, the 28-year-old Osaka has never had the same success on the natural surfaces. Before 2026, Osaka had reached the third round at the French Open three times, and the same round at Wimbledon on three occasions, but had never gone beyond.
Though she had shown flashes of improvement on both surfaces in recent years, she couldn't quite figure it out. But this season, it seems as if everything has clicked on the once-unfamiliar surfaces. She even reached her first grass-court final last week at the 500-level Bad Homburg, before having to retire from the match as a precaution with a foot injury.
"[I] understand grass-court tennis a lot more," Osaka told reporters Friday. "I think when I was younger, I was a little bit more stubborn on how I wanted to play on this surface, but I realize it's a lot more free-flowing."
And now, just like at Roland Garros -- and Madrid and Indian Wells earlier this season -- Osaka will have to take on world No. 1 Aryna Sabalenka on Sunday in the round of 16. Sabalenka, also a four-time major champion, is looking for her first Grand Slam title away from the hard court as well, but has reached the final at the French Open in 2025 and is a three-time semifinalist at Wimbledon. And no woman has been more consistent at Slams in recent years. She has reached the quarterfinals or better at her last 14 major appearances.
Osaka, who missed the entirety of the 2023 season on maternity leave, has reached a semifinal just once since her last major title in 2021.
Naomi Osaka reaches the fourth round for the first time with some wonderful displays 👏 pic.twitter.com/soAlhTmB72
— Wimbledon (@Wimbledon) July 3, 2026
Sabalenka has won all three of her meetings with Osaka this year, although the world No. 1 said every match between the two has been "very tough." In Paris, and as the only women's match of the tournament to be featured in the marquee night session spot, Osaka capitalized on early errors from Sabalenka to speed out to a 2-0 lead -- but then Sabalenka raised her level. Employing her power, aggression and variety, Sabalenka had 12 aces on the day and 39 winners for a 7-5, 6-3 victory.
After that defeat, Osaka went back home to the United States to train. Because there is no grass court near her home, she said her coach, Tomasz Wiktorowski, had to get creative in their preparation. Doing a number of "weird drills," many of which forced her to come forward, Osaka said they all helped her understand the speed and depth of the ball.
"I would say he challenges me a lot to think outside the box," she said. "... We were just doing a lot of different things."
It seems to have worked. Since the defeat by Sabalenka, she has earned a 7-1 record on grass. In that span, she has dropped just one set -- in the Bad Homburg final against Karolina Muchova before stopping the match -- and has been dominant during her run at the All England Club. Against Kasatkina, a former Wimbledon quarterfinalist, Osaka was in control from the start. She lost just five points on serve in the opening set. Even when Kasatkina raised her level in the second set, Osaka stayed the course and overcame a three-deuce game to get the break for 4-3 and didn't falter again.
The victory marked her first time reaching back-to-back fourth rounds at majors since the 2020 US Open and 2021 Australian Open. She won both of those titles.
After winning her match early in the day Friday, Osaka was uncertain if she would next play Sabalenka or Jelena Ostapenko when speaking to reporters. But that didn't stop the questions about Sabalenka, her proven obstacle, and how she would fare against her in their first meeting on grass.
"Obviously I've been doing really well on grass this year. My confidence is pretty high," Osaka said. "For me, I know what my grass-court tennis looks like. It gives me a pretty stable mindset going into the match no matter who I play.
"I also don't really have as many doubts as I did on clay court. Maybe it would be a little bit better for me [against Sabalenka] on grass. But I'm not so sure."
Though Sabalenka recorded a 6-4, 6-4 victory over Ostapenko on Friday, she has struggled at times during the grass-court season. Playing in Berlin last month, her lone warmup tournament on the surface, she needed three sets to escape Nikola Bartunkova, the current world No. 48, in the quarterfinal and then suffered a staggering defeat to Jessica Pegula in the semifinals, in which she was bageled in the deciding set.
"Honestly, I had a laugh after that third set," Sabalenka told reporters at Wimbledon about the lopsided loss.
Against McCartney Kessler in the second round at the All England Club, Sabalenka trailed 5-2 in the second set but found a way to save four set points and ultimately win the match 6-1, 7-6 (9). She later called it a "tough battle" and said she was pleased with how she managed it.
After her victory Friday, Sabalenka said there would be few surprises in the fourth-round match with Osaka. "She's aware of my power and aggression and everything," she said. And Sabalenka said she wouldn't be thinking about their previous encounters.
"Whenever I play someone back-to-back-to-back, it's always something new I'm bringing on court," Sabalenka said. "For me it's a new story every time I play someone. Every tournament, I have to play someone, for me it's a new match. I don't really care about what happened in the past.
"I think that's really been working well for me in terms of bringing the best tennis, being focused, being really motivated. For me, [it] doesn't really matter how many times I will play someone in a year, I will just go out there and bring the fight and I'll do everything it takes to get through."
When asked about playing an opponent she had played so many times this season, and if it could be discouraging with her 0-3 head-to-head record in 2026, Osaka struck a more optimistic tone.
"I think from my end, I don't mind playing someone recently," Osaka said. "Even if I look at my results, I have only lost to like her and Iga [Swiatek] for the past couple months. ... Also, [Sabalenka is] the No. 1 player in the world. If there is someone I had to lose to, I would pick that ranking position.
"If anything, I would say I learned from all of those matches, so hopefully I can apply, if I do play her."