"I have to give all credit to my coach. He knows pole vault inside out and he's the reason I'm here."
Her family were also in the stadium. "You could hear them. It's the most incredible thing, so, so special," she said.
The Tokyo Games in 2020 were always McCartney's big goal, but the speed of her progress in the past year have forced a re-evaluation of what might be possible.
Back home, members of her club North Harbour Bays Athletics club gathered to watch McCartney on the world's biggest stage.
Women's club captain Zoe Ballantyne couldn't contain her emotions when her friend nailed the jump of her life.
"I actually had tears watching her when she made that jump. I definitely knew she had it in her but still it's just so amazing that she actually did it," she said.
"She's just one of those people who you know is going to leave it all out there."
Ballantyne had no doubt McCartney was capable of winning gold in Tokyo in 2020.
"She's so young and she's got so much potential."
Her New Zealand manager Scott Newman said he was "astounded" by her success.
He had not expected her to out-jump the competition, and a top-eight finish would have been a win.
