Underdogs Osaka and Auger-Aliassime light up US Open with quarter-final runs

Osaka, smiling through her upset of Coco Gauff, said she was learning to “be grateful” and have fun again, while Auger-Aliassime credited a calm head after years of injuries and confidence struggles.

The U.S. Open's Labour Day Monday largely belonged to the underdogs, as Naomi Osaka and Felix Auger-Aliassime delivered commanding performances that carried them back to Grand Slam quarter-finals after years in the wilderness.

Osaka looked every bit the four-time major champion while dismantling third seed Coco Gauff 6-3 6-2 in 64 minutes, making her first Flushing Meadows quarter-final in five years with a display that mixed power with poise at Arthur Ashe Stadium.

"I'm a little sensitive and I don't want to cry. I had so much fun out here," said Osaka, whose smile never left her face during the dominant victory.

"A big thank you to my team. We've been through a lot, it hasn't been easy but they have been by my side."

For Gauff, defeat marked another chapter in a challenging post-French Open period. Despite serving better than she had all tournament, the American made crucial errors from the baseline in areas where she typically excels.

"Today she was definitely on paper the underdog," Gauff said of her 23rd-seeded opponent, acknowledging the upset.

Auger-Aliassime delivered his own statement with a cool 7-5 6-3 6-4 victory over 15th seed Andrey Rublev, reaching his first major quarter-final since the 2022 Australian Open after battling through injuries and confidence struggles.

"Today is my first time playing on Arthur Ashe in a few years. It feels even better than the first time," the beaming 25th seed said.

"In 2021 I was on my way back and had a few setbacks and injuries, struggles with confidence. To come back here for the second time, it feels better and more deserved."

Iga Swiatek continued her incredible season with a 6-3 6-1 thumping of 13th seed Ekaterina Alexandrova in 64 minutes, the 24-year-old becoming the youngest woman to reach the quarter-finals of all four majors in a single season since Maria Sharapova in 2005.

Breakthrough moments

Both underdogs credited their improved mental approaches for their breakthrough moments with Osaka emphasising wanting to "be grateful" and have fun against top rivals while Auger-Aliassime stressed staying "calm-headed in those big pressure moments".

Canadian Auger-Aliassime next takes on eighth seed Alex de Minaur after the Australian outclassed Leandro Riedi 6-3 6-2 6-1, while Japan's Osaka will meet 11th seed Karolina Muchova after the Czech beat Marta Kostyuk 6-3 6-7(0) 6-3.

There was little drama in the evening session as defending champion Jannik Sinner reached his eighth consecutive Grand Slam quarter-final with a 6-1 6-1 6-1 win over 23rd seed Alexander Bublik of Kazakhstan.

Bublik, who defeated the Italian on grass in their previous meeting in the Halle final in June, was given a harsh lesson on the hardcourts of New York after a draining five-set win over Tommy Paul last time out.

The top seed negated Bublik's unorthodox brand of tennis with precision from both the baseline and the net to set up an encounter with fellow Italian Lorenzo Musetti, who outclassed Jaume Munar 6-3 6-0 6-1.

"It's great to see. Italian tennis is in great form. We have so many players and different game styles," Sinner said.

"Lorenzo is one of the biggest talents we have in our sport. I'm looking forward to this one. From an Italian point of view, it's great to have for sure one Italian player in the semis."

After Sinner dazzled under the main showcourt lights for the first time in New York this year, American eighth seed Amanda Anisimova powered past Brazilian Beatriz Haddad Maia 6-0 6-3 to book a match-up with Swiatek.

Venus Williams continued to defy age and expectations as the 45-year-old and partner Leylah Fernandez reached the doubles quarter-finals with a 6-3 6-4 win over Alexandrova and Zhang Shuai at Louis Armstrong Stadium.