Emma Raducanu triumphed in a marquee showdown of former Grand Slam champions in the Mubadala Citi DC Open second round, defeating wild card Naomi Osaka 6-4, 6-2 to reach the third quarterfinal of her season.

Washington, D.C.: Draws | Scores | Order of play

Raducanu advances to the last eight in Washington for the third time in as many appearances. She has fallen to the eventual champion at that stage both times previously -- to Liudmila Samsonova in 2022 and to Paula Badosa in 2024. The Briton next faces another former Top 3-ranked wild card, Maria Sakkari, against whom she has not dropped a set in three prior meetings.

Four-time major winner Osaka and 2021 US Open champion Raducanu had never previously faced each other. Here are the key takeaways from their first ever encounter.

Raducanu's superb serving was key

In Osaka's Slam-winning years, the Japanese player's formidable delivery, which has reached a speed of 127mph, was the lynchpin of her game -- not just for its power but its reliability in important moments. But Raducanu turned a contest that featured few extended rallies into a serving contest, and came out on top.

Though Osaka tallied more aces, five to four, Raducanu's service games were bolstered by many more service winners that still counted as cheap points from the stroke. Crucially, she kept the differential between her first and second serves to a minimum, winning 29 out of 39 points behind the former and 11 out of 18 behind the latter. By contrast, Osaka's first serve may have been near-impenetrable -- she conceded just three points against it -- but Raducanu punished her second delivery relentlessly.

'I'm really pleased with that match,' she said in her post-match press conference. 'I thought that it was pretty mature, and I was holding onto my own service games really well. I knew going into the match that Naomi has been playing good, loves the hard court. So I was going to have to play well and manage my own service games, because she's very dangerous, hits a big ball, and serves extremely well. Very pleased with how I managed all the situations there.

'...Naomi is pure speed, which is very difficult to deal with, especially on these courts, where it's very lively. It was extremely important to start the point well on my serve.'

Osaka won just nine out of 28 second-serve points. Paired with a first-serve percentage of just 46% and a tally of seven double faults, that was a recipe for getting broken three times.

Raducanu, meanwhile, faced just two break points, one at 2-1 in the second set and one serving for the match. She saved both, the first with a forehand helped by a net cord and the second with -- naturally -- a service winner.

'I knew I was going to have to manage my own service games, which I'm really proud of how I did,' Raducanu said in her on-court interview. 'Then I was making inroads into her service games once I got used to it a bit ... If you float the second serve in, Naomi's going to crunch it. I had to trust my abilities in the second serve and go for it.'

Osaka's inconsistency off the ground cost her

Unable to rely on her serve, the quality of Osaka's baseline game was all the more important for her. It did not come through with any consistency. She fired 19 winners, but also committed 38 unforced errors, with the backhand in particular misfiring repeatedly. The few small opportunities she had of gaining any momentum, such as the rare sight of consecutive backhand winners in the fourth game of the second set, were quickly snuffed out, either by Raducanu's serve or a relapse into error.

Raducanu played a more conservative baseline game, striking eight winners off the ground -- but she was able to up the ante when she needed to, with a pair of exquisitely placed forehand winners down the line particular highlights.

Could this week prove to be another breakthrough for Raducanu?

Nearly four years have passed since Raducanu's fairytale run to the 2021 US Open crown as a qualifier. She has yet to reach another final, and has only made two further semifinals (Seoul 2022 and Nottingham 2024). Could that change this week?

Raducanu has dominated her matchup with former No. 3 Sakkari, whom she has defeated at the US Open 2021, Wimbledon 2024 and Dubai 2025 -- all without losing more than four games in any set. The winner of that quarterfinal would face either No. 4 seed Clara Tauson or Anna Kalinskaya in the semifinals. Raducanu has yet to face Kalinskaya, but Tauson -- who needed 3 hours and 10 minutes to get past qualifier Caroline Dolehide in the second round on Wednesday -- would be an intriguing test.

Both born in 2002, the pair were frequent junior rivals -- or at least, they met often. Tauson won all three of their meetings at that level.

In the pros, they've split two encounters. Raducanu was a 6-4 6-2 winner in the 2020 Sunderland ITF W25 semifinals, and Tauson was a 6-1, 2-6, 6-4 victor in a barnburner of a final at the 2021 Chicago WTA 125 -- Raducanu's last tournament before that Flushing Meadows title run.