Britain's Emma Raducanu is through to the quarter-finals of the women's singles at the Washington Open after beating four-time Grand Slam winner Naomi Osaka in straight sets.

After previously upsetting Ukrainian seventh seed Marta Kostyuk in round one, the 22-year-old produced a dominant performance to overcome former world number one Osaka 6-4 6-2.

The 2021 US Open women's singles champion will face wildcard Maria Sakkari in the last eight after the Greek player knocked out American second seed Emma Navarro.

Raducanu, who will replace Katie Boulter as British number one when the WTA rankings are updated on Monday, is also through to the semi-finals of the women's doubles.

She and partner Elena Rybakina overcame Giuliana Olmos and Aldila Sutjiadi 7-6 (8-6) 6-4 to set up a last-four meeting with second seeds Shuai Zhang and Taylor Townsend.

American Venus Williams, who became the second oldest woman to win a WTA Tour-level match earlier in the week, lost 6-2 6-2 to Polish fifth seed Magdalena Frech.

And in the men's singles, Britons Cameron Norrie and Dan Evans were eliminated in the last 16.

British number two Norrie lost to 14th seed Brandon Nakashima 7-6 (7-3) 6-3.

After a tight first set was decided by a tie-break, American Nakashima twice broke Norrie's serve in the second to reach the quarter-finals.

Evans, who won the tournament in 2023, fought back from 5-3 down and saved a match point to force a tie-break in the second set against Corentin Moutet but the Frenchman prevailed in straight sets, winning 6-2 7-6 (7-4).

Raducanu won the first set in 38 minutes after successfully converting her only break point in the fifth game.

She then immediately broke Osaka's serve at the beginning of the second set and after saving a break point in the fourth game, broke her serve for a second time to take a 4-1 lead.

With Japan's Osaka serving to stay in the match, Raducanu could not convert her first match point in the seventh game.

But after spurning a second match point and saving a break point, Raducanu completed the victory at the third attempt, winning the second set 6-2.

Speaking to Sky Sports after the match, she said: "I thought it was going to be a really difficult match.

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

"I knew I was going to have to play well and manage my own service games, which I'm really proud of how I did. I was making some inroads in her service game after I got used to it a little bit.

"I'm really pleased with how I handled the ball speed and conditions here in DC."

Seven-time singles Grand Slam Williams, 45, had gained entry to the tournament via a wildcard, having not played since March 2024.

By beating world number 35 and fellow Peyton American Stearns, who is 22 years her junior, 6-3 6-4 in the first round she became the oldest woman to win a singles match on tour since Martina Navratilova at the age of 47 in 2004.

She found it a harder task against Frech losing in one hour and 13 minutes, but said she was happy with her comeback.

"I had so much fun," she said. "Not the result I wanted (but) I got to play a lot of matches, definitely a plus. I couldn't be happier.

"I ran out of gas today unfortunately... sorry to have fell short. But I know I can play better and I know I will play better."

Williams is set to play in next month's Cincinnati Open after being given a wild card.