Proud patriot Alex de Minaur is pledging to "do one for Australia" when his status as an honorary Brit is temporarily suspended for his US Open Ashes battle with English No.1 Jack Draper.

De Minaur and Draper will clash for a coveted semifinal spot at Flushing Meadows on Thursday morning at 3:15am (AEST).

De Minaur, who is in a relationship with British tennis star Katie Boulter, relished the Brits embracing him at Wimbledon after all the home hopes were eliminated, at the time saying: "I'll take all the support I can get. I can be the honorary Brit here."

But seven weeks on de Minaur stands between Draper and Britain having their first US Open semifinalist since former world No.1 Andy Murray won the title in 2012.

"Look, I've played plenty of Brits. It's never easy. I feel a little bit of hostility in their country at the moment," de Minaur said.

"But again, these are the types of matches I want to be playing. I worked so hard to put myself in this position throughout the years.

"So many hours off the court, on the court, working on little things, because these are the matches I want to be playing — tail end of slams, opportunities, quarterfinals.

"I'm excited for the battle … I mean, do one for Australia, do one for myself as well."

On paper, the 10th-seeded de Minaur, contesting his third straight grand slam quarterfinal of the year, should beat the 25th-ranked Draper.

He has beaten Draper in all three previous encounters between the two.

But de Minaur knows matches aren't won on paper, especially against an inspired opponent who has not dropped a set en route to the final eight and who has conceded just 26 games in four matches.

"The biggest thing that we need to understand is that there is nothing sure in tennis," de Minaur said.

"Doesn't matter how many times you've played someone. It doesn't mean much.

"So playing Jack, he's coming off his best year by far. He's playing with a lot of confidence. He's got some very big weapons; his serve, backhand, and forehand at times.

"So it's always tough facing someone like him, especially a leftie.

"I have had some success in the past. I'm going to try and draw on that, on what I was able to do in those types of matches.

"And it's the quarterfinals of a slam. I'm going to go out there and give it my all and compete, and these matches are there to be won. Being passive is not going to get the job done."

After arriving in New York underdone and not even sure if he could play, having been sidelined since withdrawing from a scheduled Wimbledon blockbuster quarterfinal with Novak Djokovic, de Minaur is almost pinching himself to be where he is now.

"It's been a whirlwind," he said.

"The last seven, eight weeks, I've dealt with a lot of emotions, a lot of experiences that have taken a big chunk of my energy and resources.

"Coming in, I didn't have too many expectations. The hip wasn't close to 100 per cent. It wasn't feeling amazing. I just was going to go out there and see what I was able to do.

"Slowly it's been feeling better and better each day. So all of a sudden, everything has happened with the draws, a lot of upsets, and you're staring at this opportunity.

"In a way, it's been a blessing in disguise because I haven't put too much pressure on myself because I know how I felt with my hip.

"But at the same time, every day I felt better and better. So it's hopefully I'm peaking for the right moment".

The winner will face either world No.1 and reigning Australian Open champion Jannik Sinner, or fifth-seeded 2021 US Open champion Daniil Medvedev in the semifinals on Saturday morning (AEST).

Emma Navarro rode a stunning turnaround right into her first grand slam semifinal, beating Paula Badosa 6-2, 7-5 at the US Open to follow up her upset of defending champion Coco Gauff.

Taylor Fritz then earned his first berth in the final four of a major, beating 2020 US Open runner-up Alexander Zverev 7-6 (2), 3-6, 6-4, 7-6 (3).

Fritz had been 0-4 in grand slam quarterfinals but finally broke through against Zverev, the No.4 seed he also defeated in the fourth round at Wimbledon.

"I've had a lot of looks at quarterfinals over the last couple of years and today just felt different," Fritz said. 

"I really felt like it was my time to take it a step further."

Frances Tiafoe could give the US a third semifinalist — and a guaranteed chance to play for a championship — when he faces No.9 Grigor Dimitrov about 10am Wednesday morning (AEST). 

"That could be crazy, so I guess we'll see what happens," Fritz said. 

"But either way I'll be ready to go."

He controlled the action behind his strong serving, winning 20 of 21 points on his first serve in the fourth set and 81 per cent in the match. Zverev said Fritz played a good match, but he was frustrated by his own play that he said was terrible.

"I mean, at some point I didn't know what to do anymore. At some point I just had so many questions in my mind," Zverev said. 

"I had absolutely no idea whether I should go for it, whether I should put the ball on the court. Then I tried to put the ball on the court, it would go bottom of the net. A few shots I went for it, they flew … I was missing by, like, 6 feet, regular baseline shots."

On the women's side, Navarro was trailing 5-1 in the second set and was three points from having to go to a deciding third before she won the next four points to stay alive, starting a stretch in which she captured 24 of the final 28 points of the match.

"I think things weren't looking great there in the second set, but just tried to be really tough, stick in there, make her hit one more ball," Navarro said. 

"I felt like if I could scrap out a few longer points, maybe put some pressure on her, I felt like I could come back and maybe close it out in two sets.

"Happy with how I was able to do that."

Navarro, the No.13-seeded American who had never even won a match in the main draw of her home major before this year, advanced to face No.2 Aryna Sabalenka, who beat seventh-seeded Zheng Qinwen 6-1, 6-2.

AAP/AP