The 32-year-old has just sent tennis officials scrambling through the record books after qualifying for the Open's main draw for a first time.
Historians could only confirm Hunter is the first active Australian player to successfully qualify for all four grand slams, a rare feat few others from anywhere have accomplished.
Hunter didn't do it easy, taking out compatriot and great mate Maddison Inglis in her first match, fending off two match points in her second and waiting through a 24-hour weather delay to advance with a third straight sudden-death victory.
"This is the last slam on my list to tick off to get through qualies and coming in I hadn't played many singles matches in the last few months so, yeah, it feels amazing," Hunter said.
Having missed more than a year after rupturing an Achilles tendon, Hunter is back in the Flushing Meadows main draw for a first time since 2023.
Her "reward" is a first-round tussle on day one with the 11th-seeded Kostyuk, who is coming off charges to the last four at both Roland Garros and the All England Club.
"Yeah, it's yeah tough," said the one-time world No.1 doubles ace.
"She's obviously having a really good year. She's a great player, very physical with the way she plays and a really good competitor.
"So it's going to be tough. Obviously a very quick turnaround from playing qualities to my first round tomorrow, but I'm feeling good and she's the one who's under all the pressure to play against me and I have practised with her before.
"I know what her level is and I know it's going to be a challenge, but I'm up for a challenge. It's going to be fun. I'm going to enjoy it.Â
"There's been lots of times in my career I didn't think I'd be back playing at this level, so to be back in the main draw of a slam is awesome, and I'm just going to go out and enjoy it and give it a good crack."
Hunter is among six Australians playing on Monday.
Kim Birrell faces Petra Marcinko, Talia Gibson also plays a Croatian in veteran Donna Vekic and fellow rising star Taylah Preston takes on American Alycia Parks.
Adam Walton, up against China's Yibing Wu, and Aleksandar Vukic playing Japan's Rei Sakamoto are the only Aussie men in first-round action.
Sixth seed Alex de Minaur opens his campaign on Tuesday (Wednesday AEST).
