NEW YORK (AFP) -- Carlos Alcaraz surged into the quarterfinals of the US Open on Monday, Sept. 4, as upsets dominated the women's draw with Ons Jabeur and Jessica Pegula becoming the latest highly ranked players to go crashing out.

Defending champion Alcaraz, who has only dropped one set on his journey into the last eight, produced a dominant display to overwhelm Italian world No.61 Matteo Arnaldi, winning 6-3, 6-3, 6-4 in 1hr 57min.

The 20-year-old Alcaraz is bidding to become the first man since Roger Federer in 2008 to successfully defend the US Open after winning the title for the first time last year.

The identity of the Spaniard's quarterfinal opponent will be confirmed later Monday, with Alcaraz due to face either Germany's Alexander Zverev or Italy's sixth seed Jannik Sinner in the last eight on Wednesday.

A match with Sinner would be a repeat of last year's quarterfinal classic between the two men, which set a record as the latest ever finish for a US Open game after wrapping up at 2.50am.

"I think the intensity from the beginning until the last ball, I played a really solid match, less mistakes," Alcaraz said after Monday's brisk victory.

"I'm really happy with the performance in general."

In other men's matches on Monday, eighth-seeded Russian Andrey Rublev advanced with a 6-3, 3-6, 6-3, 6-4 defeat of Britain's Jack Draper.

Rublev will face the winner of Monday's later game between Russian third seed Daniil Medvedev, the 2021 champion, or Australian 13th seed Alex de Minaur.

Pegula sunk by friendly fire

In the women's draw meanwhile, more seeds bit the dust a day after world number one and defending champion Iga Swiatek was sent packing in the fourth round.

American third seed Jessica Pegula was routed in straight sets by compatriot and close friend Madison Keys, while Tunisia's fifth seed Jabeur -- beaten in last year's final -- was ousted 6-2, 6-4 by China's Zheng Qinwen.

Pegula had gone into the US Open dreaming of a first ever Grand Slam, buoyed by victory in last month's WTA 1000 Canadian Open.

But the 29-year-old's campaign came to an abrupt halt in front of a packed Arthur Ashe Stadium as 2017 US Open finalist Keys recorded a dominant 6-1, 6-3 win in just 61 minutes.

Pegula was left with no answer as Keys unleashed a stream of 21 winners to her six.

Keys also punished her friend's shaky serve, breaking her five times on her way to wrapping up a comfortable victory.

"It's always tough having to play a friend but we've been doing it our whole lives at this point," Keys, 28, said.

"When we get on the court it's all business and when we get off the court we go back to being friends."

The 17th-seeded Keys will now face Wimbledon champion Marketa Vondrousova of the Czech Republic in the quarterfinals on Wednesday.

Ninth seed Vondrousova booked her place in the last eight with a battling win over unseeded American Peyton Stearns, coming from a set down to win 6-7 (3/7), 6-3, 6-2.

Vondrousova made history in July after becoming the first unseeded woman to win Wimbledon, her first Grand Slam title.

The 24-year-old has never been past the fourth round at the US Open, and admitted after her win on Monday she had surprised herself by advancing to the last eight.

"I'm very happy," Vondrousova said. "I actually didn't expect it after Wimby -- it was a lot of pressure. We'll see what happens next."

Jabeur meanwhile, who has been struggling with flu since arriving in New York, finally saw her luck run out after scrapping her way to three-set victories in her previous two games.

The Tunisian simply had no answer to 23rd seed Zheng's blend of power and precision, with the 20-year-old from Shiyan looking far sharper than her weary opponent.

"Right now I feel just super happy and excited to play in a big stadium. I had a really good performance today," said Zheng.

Zheng is China's first US Open quarterfinalist since Wang Qiang in 2019. Two-time major champion Li Na reached the semifinals in New York in 2013 and Peng Shuai did the same a year later.

Zheng will face either second seed Aryna Sabalenka -- destined to be the new women's world number one after Swiatek's demise on Sunday -- or Russia's Daria Kasatkina in the quarterfinals. Sabalenka and Kasatkina play a night game later Monday.