Eighth seed Ben Shelton outshone Stefanos Tsitsipas at the US Open on Sunday, sealing a 6-2 6-3 6-4 victory to reach the quarterfinals and boost home hopes of a first American men's Grand Slam champion in more than two decades.

Shelton next faces Carlos Alcaraz and the 23-year-old showed he has the tools to trouble the Spaniard - though he said it would take special tennis to beat the defending champion who has hit top form after an injury layoff.

"The level that he's playing at is really impressive. To not play for almost five months and do what he's doing is superhuman and we're happy to have him back," Shelton said.

"He lights up stadiums and I think there's going to be fireworks again on Tuesday."

Alcaraz defeated American Tommy Paul 6-4 6-3 6-4.

Ben Shelton celebrates victory over Stefanos Tsitsipas. Photo: IMAGN IMAGES via Reuters

Shelton blended raw power with a delicate touch and sharp decision-making to overwhelm Tsitsipas in an opening set that lasted only 31 minutes on Arthur Ashe Stadium.

"My team told me that if I didn't show up fully focused they would leave," joked Shelton, who is bidding to become the first US man to win a major since Andy Roddick's 2003 triumph at Flushing Meadows.

"I was focused, it was a good match from start to finish. It was my first straightforward match this year and I'm happy I can play this way in front of you.

"When you play on this court every year, it feels like you start over again and the nerves hit. I finally found my groove and was in a flow state. Playing on the greatest court in the world is an unbelievable feeling."

With a two-set cushion, Shelton sprinkled some showmanship into the clash in the next with a soaring overhead smash before racing away and completing an emphatic win with a comfortable hold of serve.

Meanwhile, Frances Tiafoe dispatched 2021 US Open champion Daniil Medvedev 7-6(1) 6-4 7-6(6) to punch his ticket to the quarters.

He will meet fellow American Alex Michelsen, who beat Argentine Tomas Martin Etcheverry 7-6(6) 6-4 6-4 earlier in the day.

In the women’s tournament, American Jessica Pegula clinched a resounding 6-3 6-4 win over Sorana Cirstea to reach the quarterfinals, as the Romanian player made her final Grand Slam appearance.

The 2024 runner-up kept alive her bid for a maiden major title, overcoming a resurgent Cirstea who had enjoyed a late-career renaissance, reaching a career-high top-20 ranking, before retiring at the end of the season.