Australian wildcard Rinky Hijikata has continued his audacious run through the US Open draw to charge into the fourth round at Flushing Meadows.
Hijikata resisted a stirring fightback from Chinese trailblazer Zhizhen Zhang to post a 6-3 6-3 4-6 6-3 victory over the world No.67 and scamper into the last 16 at the season's final grand slam.
"I wouldn't have picked it at the start of the week," Hijikata said.
"But I put a lot of hard work in. I've always strived for these type of results and I've always felt that I am capable of having runs in these tournaments.
"But to have it happen this soon when I feel like I am still pretty new playing at the grand slams, it's pretty cool."
The landmark win secured the 22-year-old a fourth-round date with American 10th seed Frances Tiafoe on Monday (AEST), a fresh career-high ranking inside the world's top 80 and a minimum pay day of $US284,000 ($A440,000).
That almost doubles Hijikata's earnings in an already-breakout season that featured a maiden grand slam doubles crown with countryman Jason Kubler at the Australian Open in January.
Hijiikata had announced his arrival to New York fans last year when he seized the opening set from Rafael Nadal in an electrifying first-round encounter under lights at Arthur Ashe Stadium.
But few could have predicted a year on the world No.110 would feature in the second week at Flushing Meadows, especially after Hijikata needed Tennis Australia's generosity of a wildcard entry into the main draw.
"I have developed a lot since I played Ashe at this time last year in my first grand slam and that was really cool," Hijikata said.
"I really learned a lot from that match and that experience. That has been the biggest key, I think, every week I play. I am learning more and more.
"I feel like I am a lot better player than I was 12 months ago and I still have a lot improve on."
The Sydney-born son of Japanese immigrant parents has more than vindicated TA's faith in him with an inspired run.
Moments after his first-round win over Pavel Kotov, Hijikata was left rocked by a fatal shooting at his girlfriend's college, the University of North Carolina where he also spent two years studying.
He dedicated his second-round win over Marton Fucsovics to his former schoolmates and celebrated wildly after claiming a third straight higher-ranked scalp on Friday night.
Clubbing winners off both wings, Hijikata had Zheng under the pump from the get-go.
Clearly weary from sapping five-set wins in his opening two matches, including an monumental upset victory over seventh seed and 2022 Open runner-up Casper Ruud, Zheng had to fight off eight break points in the first two sets.
But Hijikata couldn't be denied, eventually blasting to a two-set lead with three service breaks as Zheng struggled to cope with the Australian's firepower.
Bravely bidding to become the first Chinese man in the 56-year open era to make the last 16 of a grand slam, Zheng made one last stand despite needing two medical time-outs for a back issue.
Shortening the points, Zheng's bold tactics paid off as he snatched the third set after an epic service game lasting almost 10 minutes.
But the effort hurt the 26-year-old as Hijikata upped the ante and gained two decisive breaks in the fourth set before sealing victory with his 12th ace on his first match point after three hours and 10 minutes.