Young guns progress at US Open on mixed day for Aussies

Alex de Minaur has made up for lost time with a scorching second-round win at the US Open.

In a rain-interrupted match resuming from day three, de Minaur returned on Thursday to to complete a 6-3 7-5 6-3 victory over Chile's 31st seed Christan Garin.

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De Minaur was holed up at Flushing Meadows for more than six hours on Wednesday, only to get one game in before play was suspended.

But the Australian No.2 shook off the disruption and to post an impressive win to earn a shot at seventh-seeded former Open finalist Kei Nishikori on Friday.

"Very pleased with that," de Minaur said.

"Look, it's not easy, especially with what happened yesterday, to come back again today and to play at a very high level, which I did throughout the whole match.

"I fought off some very tough games on my serve and I managed to hold on to that second set, which was huge.

"I put myself in tough situations today and got myself out of them, so very happy."

Nishikori, runner-up to Marin Cilic in 2014 after taking out Novak Djokovic that year in the semi-finals, holds no fears for de Minaur.

"I will go out there and just play fearless. Ultimately, that is when I play my best tennis," the 20-year-old said.

"I can draw a lot of good feelings from last year. I had a very tough match against Cilic and I just went out there and took it to him.

"Obviously it was a little bit of a (five-set) heartbreaker but ultimately that is the way I have to play and that is what you want.

"You want to be playing these top guys at the top of their level.

"Hopefully I can really come out tomorrow and give it my best crack."

Joining his compatriot in the third round is Alexei Popyrin after the tennis prodigy overcame a horror start.

De Minaur joined by compatriot in next round

Popyrin matched his career-best grand slam run with a stirring second-round win in New York.

The just-turned 20-year-old former grand slam junior champion fought back from a set and a break down to defeat Mikhail Kukushkin 2-6 7-5 6-3 6-2 and set up a date with big-hitting Italian Matteo Berrettini.

Berrettini, the 24th seed, earlier on Thursday ended Jordan Thompson's campaign with a 7-5 7-6 (7-5) 4-6 6-1 win over the Australian No.3.

Popyrin, who ousted world No.4 Dominic Thiem en route to the last 32 of the Australian Open and also won matches at the French Open and Wimbledon, is enjoying a stunning first full season at the slams.

His latest victory, after dropping the first four games and then falling behind 4-2 in the second set, will send the 2017 Roland Garros junior champion from outside No.105 in the world to inside the top 90 - with a bullet.

Another win at Flushing Meadows and Popyrin will be headed for uncharted waters - the last 16 of a major and a possible all-Australian showdown with Nick Kyrgios, who plays French qualifier Antoine Hoang later on Thursday.

Popyrin struck 44 winners to Kukushkin's 23, including 15 aces, and broke the Kazakh seven times during the two-hour, 35-minute match-up.

Big-hitting Italian Berrettini ended Thompson's US Open campaign with a hard-earned four-set win over the Australian No.3.

Seeded 24th and boasting two titles in 2019, Berrettini was made to sweat on the hottest day of the Open before pulling out a 7-5 7-6 (7-5) 4-6 6-1 second-round victory on Thursday.

Thompson rued not closing out the opening set from 5-2 up and then dropping the second in a tight tiebreaker.

"Brutal. I could have won both those first sets," he said.

"The first set 5-3 serving, 30-15, I got a little bit negative. I lost that set quickly.

"Even though I was 5-all, 40-15, yeah it's tough. I'm up 5-3 in the second-set tiebreaker. Hit a net cord, I didn't think it was going over. It sort of just climbed over the net. He won the tiebreaker 7-5.

"I fought my ass off to win that third set. He got off to a great start in the fourth and ran away with it, and that's what he can do with his big game."

Meanwhile, Thanasi Kokkinakis was forced to withdraw from his second round match against Rafael Nadal, reportedly due to a shoulder injury.

The 24-year-old has battled consistent injuries for several years since breaking into the ATP top 100 in 2015.

Ash Barty Australia’s last remaining woman

Barty, a second-round winner over American Lauren Davis on Wednesday night, is the last Australian woman standing for the sixth straight major following Ajla Tomljanovic's exit.

Tomljanovic fought hard in searing heat before bowing out 4-6 7-5 6-2 to Estonia's 21st seed Anett Kontaveit on Thursday.

Barty was looking to raise her game after needing more than two hours to see off the 73rd-ranked Davis and three sets to beat world No.80 Zarina Diyas in her opener.

But having finished second best against Barty twice already this season, the second time as recently as this month in Cincinnati, Sakkari knows she's in for a fight regardless.

"I said last year in Indian Wells when I beat her, for me she is the best player in the WTA Tour," Sakkari said.

"And that was when she was like 14, 15 in the world. You could see how talented she is, how mentally strong she is and how calm.

"You could see was going to achieve many good things and we can see how she has played this year.

"But I also believe in myself and try my best tomorrow for the best result for myself.

"I remember I took my foot off the gas in 'Cinci', after I won the first set. So if things go well tomorrow, I will keep it in mind not to do the same mistake."