Sofia Kenin is into the Australian Open final after stunning top seed and home favourite Ash Barty 7-6(6) 7-5 on Rod Laver Arena.
The 21-year-old Kenin showed her frustration at times in the first set, throwing her racket on court, but managed to hang in and save three break points to hold for 3-3 and eventually force a tie-breaker.
With temperatures soaring to 38 degrees Celsius (100F), the American saved two set points and then converted her first to take the opening stanza and stun the crowd into silence.
But the fans soon found their voice again, belting out chants of, "Let's go Barty, let's go," as the home favourite broke Kenin early in the second set to go up 2-1.
The Australian world number one Barty looked like she would wrap up the second when she had another two set points on serve at 5-4, but Kenin rallied and broke back to seal her place in the final.
Kenin, who has never played a Grand Slam final before, will face either Garbine Muguruza or Simona Halep.
"She's [Barty] such a tough player. I know she's been playing amazingly and I knew I had to find a way to win. I'm just so grateful and thankful for this moment," Kenin said on court afterwards.
"I'm so speechless. I can't believe this. I've dreamed about this since I was five years old. I've worked so hard to get here and thanks to my Dad [also her coach] and everyone so thank you.
"She was never going to give it to me I really needed to fight out there.
"She's a great player and there's a reason she's world number one but I'm so thankful for this."