A disbelieving Magda Linette continued her dream run at the Australian Open on Wednesday with a stunning victory over former world number one Karolina Pliskova to move into the semi-finals, where she will play fifth seed Aryna Sabalenka.
Sabalenka, the only top-10 seed left in the draw, earned her place in the last four by outmuscling Donna Vekic 6-3 6-2 in a ferocious battle of big hitters in the second match on a baking Rod Laver Arena.
The Belarusian might have her hands full against unheralded Linette, who played wonderfully controlled tennis that belied her ranking of 45th in the world to wrap up a thoroughly deserved victory over Pliskova 6-3 7-5.
Linette had been expected to play second fiddle to fellow Pole Iga Swiatek at Melbourne Park but will now play a first Grand Slam semi-final on Thursday in a match that will decide who meets Victoria Azarenka or Elena Rybakina in the final.
"It's so much and I can't really believe it," the 30-year-old said. "I will never forget this. I'm breaking through some really difficult things for me. This will stay with me for life. So I'm really grateful."
Sabalenka later took her chances in a physical one-hour first set littered with break points before running away with the second to reach her fourth Grand Slam semi-final, a first in Melbourne.
Vekic had held a 5-1 career record against the Belarusian but was unable to match the level of the new, improved Sabalenka with 13 double faults not helping the Croatian's cause.
Sabalenka is not so improved that she did not make plenty of errors as well but her once-fragile serve was largely solid, and when she got her explosive forehand going it was always going to be hard for Vekic to cope.
Two double faults as Sabalenka served for the match were a reminder of the player she once was but, the 24-year-old saved three break points and sealed the win with a huge forehand that struck the running Vekic in the body.
"She's a great player and it's always tough to against play her," Sabalenka said, before explaining why she thought she had come out on top.
"I think it was because I was calm and I expected this game from her, so I was able to stay in the game no matter what. That was the key."
Linette had no problems serving out her quarter-final against twice Grand Slam finalist Pliskova, who made 36 unforced errors and was always chasing the match.
The Czech knew she had to raise her game in the second set after losing the first but Linette had the answer to everything thrown at her.
"She really played well from the baseline," said Pliskova. "I just didn't find any space in the court to go for my winners. Obviously the serve was not great today at all."
Linette had never been past the third round at a Grand Slam before arriving at Melbourne Park this year and said a change in mentality was behind her fairytale run.
"I think through all my life I've been taking mistakes, losses very personally," she explained. "So to disconnect (life) as a tennis player and a person was really difficult because I felt a lot of times that the mistakes were defining me."
Later on Wednesday, Ben Shelton and Tommy Paul meet in the first all-American men's Grand Slam quarter-final since 2007, and overwhelming favourite Novak Djokovic faces Andrey Rublev in a bid to reach a 10th Melbourne Park semi-final.