Top seed Jannik Sinner broke American hearts as he beat Tommy Paul, albeit home favourite Jessica Pegula marched into the last eight.

Top seeds Jannik Sinner and Iga Swiatek continue to blaze a trail through the US Open draws, easing into the quarterfinals of a tournament marked by almost daily upsets with a minimum of fuss.

Sinner disappointed a partisan crowd with a 7-6(3) 7-6(5) 6-1 win over Tommy Paul in an entertaining fourth-round tie after Swiatek had beaten Liudmila Samsonova 6-4 6-1 in a more muted atmosphere on the main Arthur Ashe Stadium show court on Monday.

Italian Sinner barely got a look at Paul’s serve until the third set but produced his best tennis when it mattered to subdue the effervescent American and move on to a mouth-watering last-eight meeting with 2021 champion Daniil Medvedev.

“I can be very proud today, it was a tough opponent, so I’m very happy to be in the next round,” said Sinner, who beat Medvedev in Melbourne in January to win his only Grand Slam title.

“I didn’t start very well, [but] I tried to stay there mentally. And for sure, this today was one of the keys to win this match.”

Russian Medvedev had earlier brushed aside a delay caused by a fire alarm in the building where the Hawkeye line-calling system is housed to pummel Portugal’s Nuno Borges 6-0 6-1 6-3.

Like Medvedev, Swiatek is the only former singles champion left in her draw and the Pole hit her impressive stride in a comfortable win over Samsonova before warning she was only going to improve.

“At the beginning, it wasn’t easy to get the rhythm,” the 2022 champion said of her week in New York.

“So I’m happy that I got some matches here and, for sure, I’m feeling better and better every day.”

American fans at Arthur Ashe earlier did have a success to cheer on their Labor Day holiday as Jessica Pegula efficiently disposed of Diana Shnaider 6-4 6-2 to reach the last eight without dropping a set.

The sixth seed, who missed the French Open due to injury but triumphed at a US Open tune-up event in Canada last month, said she felt her game was trending in the right direction.

“Today was the best I’ve felt off the ground so I want to keep working and bringing my best tennis for the later rounds,” the 30-year-old said.

“There’s always a lot of pressure here but I like it. It’s nice being an American here and getting all the support.”

Pegula has reached the quarterfinals of all four Grand Slams but never gone further, and her path to the semis this week is blocked by the imposing figure of world number one Swiatek.

The only minor surprise on the eighth day of the championships came when Karolina Muchova, a semifinalist here last year, ousted Italian fifth seed Jasmine Paolini 6-3 6-3.

Unseeded after surgery on a wrist injury sustained at last year’s US Open sidelined her for 10 months, the Czech showed her quality to outclass Paolini, who had reached the finals at both the French Open and Wimbledon this year.

Muchova will next face Beatriz Haddad Maia after the Brazilian produced 40 winners to send former world number one Caroline Wozniacki packing 6-2 3-6 6-3.

Final 🎱#USOpen pic.twitter.com/5RRv42dgJK

— wta (@WTA) September 3, 2024

Jack Draper was also in action at Louis Armstrong Stadium and became the first British man since Andy Murray in 2016 to reach the last eight at Flushing Meadows after a 6-3 6-1 6-2 thrashing of Tomas Machac.

The 25th seed has yet to drop a set at the tournament and will face Australian Alex de Minaur in his first Grand Slam quarterfinal on  Wednesday.

De Minaur came out on top 6-0 3-6 6-3 7-5 in a tight tussle with compatriot Jordan Thompson to reach the last eight at a third straight Grand Slam, the first Australian man to do so since Lleyton Hewitt two decades ago.

Quality quarterfinals await 🍿 pic.twitter.com/iBYsQ815KJ

— US Open Tennis (@usopen) September 3, 2024