Chinese pair of Zheng Saisai and Duan Yingying produced an impressive all-round display to march into the U.S. Open quarter-finals for the first time. 

The 12th-seeded duo advanced on Monday at the expense of Anastasia Pavlyuchenkova of Russia and Anastasija Sevastova of Latvia.  

Pavlyuchenkova and Sevastova were no match for Zheng and Duan who hammered down a series of great serves and won the opening set 6-4. In the second set, the pair from China were even more rampant, staying in command during the big points to seal the set 6-3 and draw the curtains on the tie. 

Zheng and Duan, who are the first Chinese pair to reach the quarters at Flushing Meadows since Zheng Jie and Yan Zi in 2009, will now face Belgium star Elise Mertens and Belarus youngster Aryna Sabalenka.

Meanwhile on Monday, top-ranked defending champion Naomi Osaka will fall from world No. 1 spot next week after suffering a 7-5, 6-4 loss to Swiss 13th seed Belinda Bencic, who matched her deepest career Grand Slam run from the 2014 U.S. Open. 

It was the 22-year-old's third victory of the year over Osaka, having also won at Indian Wells and Madrid.  

Osaka's exit means there will be four different women's Grand Slam winners in a season for the third consecutive year, a first in the Open era. 

Also moving into the last eight was Mertens, who cruised past 141st-ranked U.S. wildcard Kristie Ahn 6-1, 6-1 in 67 minutes. 

Vekic, the 23rd seed from Croatia, saved a match point in the second set and made her first Slam quarters by rallying past German 26th seed Julia Goerges 6-7 (5/7), 7-5, 6-3.

On the men's side, sixth seed Alexander Zverev rolled through the opening set against Argentina's Diego Schwartzman under the roof on a rainswept Labor Day at Arthur Ashe Stadium, but lost his way to go down 3-6, 6-2, 6-4, 6-3. 

Schwartzman, also a quarter-finalist at last year's French Open, matched his best Grand Slam run and awaits the winner between 18-time major champion Nadal and Croatian 22nd seed Cilic. 

Nadal, a three-time U.S. Open winner, has spent barely four hours on court in reaching the last 16, having benefited from a walkover in the second round. 

Later in the day, Matteo Berrettini became just the second Italian man to progress to the U.S. Open quarter-finals, 42 years after Corrado Barazzutti's run to the last four in New York. 

Berrettini, the 24th seed, eased to a 6-1, 6-4, 7-6 (8/6) win over Russia's 43rd-ranked Andrey Rublev to reach the last eight at a Grand Slam for the first time. 

Andujar, 33, will try to become the oldest player in the Open era to reach his first Grand Slam singles quarter-final as he battles Monfils, a semi-finalist at Flushing Meadows three years ago. 

(With input from agencies)