Melbourne - Unseeded Garbine Muguruza fought back from behind in both sets to defeat racquet-smashing fourth seed Simona Halep on Thursday and set up an Australian Open final with surprise-package Sofia Kenin.
The Spaniard, a two-time Grand Slam champion, reached her first Melbourne final with a tough 7-6 (10/8), 7-5 victory at a steamy Rod Laver Arena.
The 26-year-old, who suffered a calamitous drop in form last season, is the first unseeded player to reach the women's final since Belgium's Justine Henin in 2010.
"Very excited to be in the final, it's a long way to go and I have one more match on Saturday," said Muguruza, the former world number one who is now ranked 32.
"I wasn't thinking that I was down, I was thinking keep going and at some stage you're going to have an opportunity.
"Luckily I have 48 hours now to recover and get ready for the last match. We train all of our career to be able to play on this court and in (front of) this crowd."
Halep and Muguruza, who have both won the French Open and Wimbledon, were too close to split in a nervy first set.
In sweltering heat, with play on the outside courts suspended earlier as temperatures hit 38 Celsius (100.4 Fahrenheit), they grappled all the way to the tie-breaker.
Muguruza, unseeded at a Grand Slam for the first time since 2014, squandered two set points in the breaker while saving two more for Halep, and then clinched it with a stop volley that Halep couldn't get back over the net.
It was the first set that Halep - also a former No 1 - had dropped all week and she reacted by mangling her racquet and slumped in her chair, shaking her head.
The 28-year-old recovered her poise and broke Muguruza for a 3-2 lead in the second set, before Muguruza broke back and then held to make it 6-5.
Halep, so serene in Melbourne up until now, cracked as she served to stay in the tournament, saving the first match point but then netting a backhand as Muguruza surged forward on the second.
Kenin the Barty pooper
Kenin, the feisty American 14th seed, earlier stunned world number one and home hope Ashleigh Barty 7-6 (8/6), 7-5 to reach her first Grand Slam final.
Moscow-born Kenin, 21, the last American left in Melbourne, was the party pooper once more.
She had already brought the fairy tale run of 15-year-old Coco Gauff to an end in the fourth round with the aggressive style of play that has become her trademark over the past fortnight.
Kenin looked shell-shocked in the immediate aftermath of her surprise defeat of home hope Barty, saying: "She's such a tough player, she's playing really amazing. I knew I had to really find a way to win.
"I'm just speechless, I honestly can't believe this. I've dreamed about this moment since I was five years old."
"I've worked so hard to get here," added Kenin. "I really had to fight out here. There's a reason she's number one."
Kenin, who had a breakthrough 2019, winning her first three WTA titles, was contesting her first Grand Slam semi-final, and it was Barty's first time in the last four in Melbourne.
But if the locals hoped Kenin would be cowed by the occasion and her top-ranked opponent, the French Open champion, they were to be mistaken.
Results on day 11 of the Australian Open Grand Slam at Melbourne Park on Thursday (x denotes seeding):
Sofia Kenin (USA x14) bt Ashleigh Barty (AUS x1) 7-6 (8/6), 7-5
Garbine Muguruza (ESP) bt Simona Halep (ROM x4) 7-6 (10/8), 7-5