|2018 US Open|
|Venue: Flushing Meadows, New York Dates: 27 August-9 September Coverage: Live radio coverage on BBC Radio 5 live sports extra; live text commentaries on the BBC Sport website|
American Sloane Stephens continued her quest for back-to-back US Opens with a straight-sets win over Belgian 15th seed Elise Mertens in the fourth round.
Third seed Stephens won 6-3 6-3 in Sunday's night session at Flushing Meadows.
The 25-year-old is the highest ranked player left in the women's singles following early exits for Simona Halep and Caroline Wozniacki.
Stephens faces Latvia's Anastasija Sevastova in the quarter-finals.
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Only two of the top 10 women's seeds - Stephens and Karolina Pliskova - remain in the draw after world number seven Elina Svitolina was beaten 6-3 1-6 6-0 by Latvia's Anastasija Sevastova.
Czech eighth seed Pliskova beat Ashleigh Barty 6-4 6-4 to set up a meeting with Serena Williams in the quarter-finals.
Williams beat unseeded Estonian Kaia Kanepi to advance and looks every bit the contender for a record-equalling 24th Grand Slam title - even if she is seeded 17th following her return to tennis after having a baby.
Pliskova saved eight break points on her way to beating Australian 18th seed Barty as she held her nerve to withstand the pressure from the 22-year-old, who delivered 29 winners to the Czech's 16.
"It was very tough even though the score looks easy," said Pliskova, who was runner-up here in 2016. "I'm very happy to be through."
While many of the highest-ranked players have fallen, there are still three former champions still in - Maria Sharapova, Williams and Stephens, as well as last year's runner-up Madison Keys.
If Stephens gets past 19th seed Sevastova then Williams - the last women to defend the US Open title in 2014 - could await her in the semi-finals.
Stephens in command against Mertens
Stephens fought off two break points in the opening game, but the match turned in her favour in the fourth when Mertens buckled under intense pressure to double fault on break point.
The Belgian, who was aiming to reach a career-high top-10 ranking with a strong run in New York, immediately restored parity in the next game, only to see Stephens take control again by winning the final three games of the set.
Stephens continued to land first serves at a high percentage - finishing with an 83% success rate - and in the end it was Mertens' serve which crumbled.
Stephens won 12 of the final 15 points to break twice more on her way to winning what proved to be the final four games.