Alex de Minaur stuns World No.7 in stunning career firsts

Alex de Minaur isn't finished yet after claiming the biggest scalp of his career to surge into the US Open fourth round in New York.

De Minaur followed his equally impressive compatriot Ash Barty into the fourth round after wowing fans on The Grandstand with a 6-2 6-4 2-6 6-3 triumph over seventh-seeded former Open runner-up Kei Nishikori.

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The superb win rocketed the 20-year-old livewire into the second week of a grand slam for the first time.

De Minaur hadn’t beaten a top-10 player in his previous 11 attempts, with his triumph against Nishikori ranking among the biggest wins of his fledgling career.

The pulsating victory leaves de Minaur one win away from a potential quarter-final showdown with Roger Federer.

But he's keeping his feet firmly on the ground ahead of a last-16 match-up on Sunday with either Grigor Dimitrov or Polish qualifying lucky loser Kamil Majchrzak.

"It's just another day. Nothing changes. My mentality going in is going to be the same," de Minaur said.

"You know, I'm just happy to be here. There's not much to complain about. I'm in New York, playing the US Open, some great weather, and playing some great tennis.

"Hopefully I can just keep it rolling. I'll take it as a big opportunity, as I did for this match. This is where I want to be, so I'll go out there and leave 100 per cent. Nothing changes."

His watershed win over Nishikori atoned for a gut-wrenching five-set loss at the same stage last year to Marin Cilic, the Croatian who beat the Japanese superstar in the 2014 final at Flushing Meadows.

"Obviously last year was a bit of a heartbreaking match for me. Very big opportunity leading two sets to love up against Cilic and then losing in a heartbreaker 7-5 in the fifth. It stung a lot," de Minaur said.

"But you learn so much from it. You know that that's your level. It helped me a lot today.

"At one stage it looked like maybe the same thing was going to happen, but I just had to regroup and put out all those negative thoughts in my head and just play point by point, just make sure to be very positive and leave it all out there, intensity.

"And I'm glad I was able to do that, play a great game in the fourth set to break him, and then sort of hold on to my serve."

The winner of hardcourt titles in Sydney and Washington this year, de Minaur has earned himself a huge opportunity to make his maiden grand slam quarter-final.

If he gets through his next match with either Dimitrov or Majchrzak, he face either Federer or the winner of Friday's third-round match between David Goffin and Pablo Carreno Busta.