Melbourne - Simona Halep came through a three-set thriller against Angelique Kerber on Thursday to set up a winner-takes-all Australian Open final against Caroline Wozniacki, where the number one ranking will be on the line.
The Romanian top seed battled past former champion Kerber 6-3, 4-6, 9-7 and now faces an enticing showdown against the number two seed, with both chasing a maiden Grand Slam title.
Wozniacki beat unseeded Belgian Elise Mertens 6-3, 7-6 (7/2) after a late wobble when she was broken serving for the match at 5-4 in the second set.
"Halep, just like me, was down match points early on in the tournament," said Wozniacki. "I think it's exciting because we're both playing for the number one ranking."
Saturday's final, which could be played in forecast temperature of up to 35 degrees Celsius, looks set to be a gruelling do-or-die clash between two players known for their tenacity and court coverage.
"I respect her a lot, and I know it's going to be similar. I will have to run, so a very good rest after this match," said Halep.
"I want to give my best to believe that I have the chance to win and not to think about the title. If it's going to come, it's going to come."
In a see-sawing contest, Halep sprinted into a 6-3, 3-1 lead against Kerber before the 2016 Melbourne Park winner, seeded 21, fought back.
The Romanian finally prevailed in 2hr 20min with her fourth match point to ensure a new name will grace the trophy.
"Definitely was very tough. I'm shaking now. I'm really emotional right now because I won this match," said Halep, who saved two match points.
"I knew it was going to be tough. She is hitting from everywhere, I'm glad I could resist. Thank you everyone for supporting me, you helped me."
Halep scampered to the first set in 25 minutes and, after dropping the second set against the run of play, squandered two match points in the third before saving two from Kerber as she served for the match at 6-5.
"I said if she come back I could do it. I had confidence in myself," said Halep.
"I tried to be calm today. It was a rollercoaster, up and down. If you don't give up you can win. I did it well. I am proud of myself."
In her match, Wozniacki almost let Mertens back in when serving for the win at 5-4, and seemingly in complete control.
Two double faults enabled the Belgian, in her first semi-final at this level on her Australian Open debut, to level at 5-5.
Serving to take it to a tiebreak at 5-6 Wozniacki then needed to save three set points before sealing the match in the tiebreak.
"It means so much to me." said the Dane after reaching her maiden Australian Open final and her first Grand Slam decider since 2014.
"I'm really happy and proud of how I've managed to turn things around when things weren't going my way and keep it up whenever it was going my way."
The final will be only the 17th time in Australian Open history that the number one and two seeds have met for the title - both first and second seeds have won eight times each.
The last time it happened was in 2015 when top seed Serena Williams beat second-seeded Maria Sharapova.