Naomi Osaka delivered a statement win at the US Open by thrashing home favorite Coco Gauff in the last 16 on Monday as Iga Swiatek rolled into the quarter-finals.

The Japanese star powered past third seed Gauff 6-3, 6-2 in a highly-anticipated but lopsided fourth-round showdown of former US Open champions on the Labor Day holiday in New York.

Osaka broke in the very first game in front of an expectant Arthur Ashe Stadium crowd and was untouchable on serve in a ruthless display against a misfiring Gauff, who hit 33 unforced errors.

"This is my favorite court in the world and it means so much to me to be back today," said Osaka, who looks primed for a tilt at a fifth Grand Slam.

"I'm a little sensitive and I don't want to cry. I had so much fun out here."

The 27-year-old, a two-time US Open champion, is enjoying her deepest run at a major since winning her second Australian Open title in 2021.

It has been a painstaking climb back towards the top of the game for Osaka, who returned to tennis last year following the birth of her daughter in 2023.

"I was in the stands two months after I gave birth watching Coco and I just really wanted an opportunity to come out here and play," said Osaka, who also beat a 15-year-old Gauff at the US Open in their first meeting in 2019. 

She will play Czech 11th seed Karolina Muchova or Ukrainian 27th seed Marta Kostyuk in Wednesday's quarter-finals.

Swiatek brushed off Russian 13th seed Ekaterina Alexandrova 6-3, 6-1 in barely an hour to extend her Grand Slam winning streak to 11 matches as she targets a second US Open crown. 

"I felt like in the beginning she played fast but later on I felt in my bubble, in the zone," said Swiatek. "I'm happy with the quality and my serve."

The Polish second seed could face Amanda Anisimova next in a repeat of the Wimbledon final, which Swiatek won 6-0, 6-0. The American plays Brazilian 18th seed Beatriz Haddad Maia later on Monday.

Swiatek has reached the last eight or better at all four majors in a season for the first time and is chasing her seventh Grand Slam.

De Minaur, Auger-Aliassime progress

Men's eighth seed Alex de Minaur sealed a quick passage to the quarter-finals with a 6-3, 6-2, 6-1 win over Swiss qualifier Leandro Riedi.

De Minaur put the world number 435 to the sword with eight breaks as he swept into a sixth Grand Slam quarter-final. He has never made it past the last eight though. 

"Ultimately this is where I want to be -- I want to be playing for big titles, I want to be in contention," said De Minaur, into his third US Open quarter-final.

He advances to play Felix Auger-Aliassime, who defeated Andrey Rublev in straight sets as the Canadian 25th seed reached his first Grand Slam quarter-final in three years.

Auger-Aliassime won 7-5, 6-3, 6-4 for just his second victory over the Russian in nine attempts.

The 25-year-old Auger-Aliassime's best run at a Grand Slam came when he advanced to the semi-finals of the US Open in 2021.

"It feels even better than the first time," Auger-Aliassime said of returning to the last eight in New York.

"I think the first time at 21 I was kind of on my way up. To have a few setbacks, injuries, struggles with confidence... to come back for a second time to the quarter-finals here, it feels much better."

World number one and reigning men's champion Jannik Sinner takes on Alexander Bublik in the night session.

Sinner is trying to become the first man to defend the US Open since Roger Federer won the last of his five successive titles in 2008.

However, the mercurial Bublik is one of only two players to beat Sinner this year. Carlos Alcaraz is the other.

Italian 10th seed Lorenzo Musetti plays unseeded Spaniard Jaume Munar with both seeking to reach a first US Open quarter-final.

by Martyn Wood