Emma Raducanu overcame another former US Open champion, Naomi Osaka, in straight sets to reach the Washington Open quarter-finals.

The 2021 Flushing Meadows champion won 6-4 6-2 in one hour and 21 minutes to tee up a last-eight clash with Maria Sakkari, who upset Emma Navarro earlier on Thursday.

The first meeting between Raducanu and Osaka started with four straight holds of serve, before Raducanu broke off the back of a double fault from her opponent.

That proved enough to give the Brit the first set, and she stepped things up a notch in the second set, taking another break at the first attempt.

Raducanu had to fend off break point at 2-1 up, but after coming through that service game, the 22-year-old broke again – helped by another double fault from Osaka – and cruised through the remainder of the contest. 

"I thought it was going to be a really difficult match," said Raducanu in her on-court interview afterwards. 

"Naomi has won four slams, been world number one, she's so dangerous and on the hard courts I think she's particularly comfortable.

"I knew I'd have to play really well and manage my service games. 

"I'm really proud of how I did. I'm really pleased with how I handled the ball speed and the conditions."

Raducanu will meet Sakkari for a place in the semi-finals, having never previously dropped a set against the Greek in their three head-to-head meetings.

Raducanu said of Sakkari: "We've played a few times, I think the conditions really suit her, she enjoys playing her, she took out the second seed yesterday, so she's in great form."

Making a statement @EmmaRaducanu battles past Osaka 6-4, 6-2 to return to the quarterfinals in Washington DC.#MubadalaCitiDCOpen pic.twitter.com/9ffyJOTXNy

— wta (@WTA) July 24, 2025

Data Debrief: Mistakes cost Osaka

Osaka impressed in a 6-2 7-5 victory over Yulia Putintseva in the first round, but she was error-prone from the off on Thursday.

She made seven double faults and when forced onto second serve, only managed to win 45% of points as Raducanu's speed across the baseline prevailed.