A contagion has swept Melbourne Park, laying waste not only to the high seeds but to defending champions and their Australian Open streaks, too.
Stanislas Wawrinka and his beautiful backhand undid Novak Djokovic on Tuesday night, and on Wednesday the sublime Agnieszka Radwanska shredded Victoria Azarenka's hat-trick hopes with shots as artful as brushstrokes.
Azarenka, the second-seeded Belarusian, followed the premature path to the departure lounge beaten by top seed Serena Williams and No.3 Maria Sharapova. She went down not only screaming but in a screaming heap, smashed 6-0 in a deciding set she had entered full of momentum.
Fourth seed Li Na is now the highest-ranked survivor in the women's draw, although if Radwanska can reproduce the most irresistible tennis played by any man or woman at the tournament - first in Thursday's semi-final against Dominika Cibulkova and then a final against either Eugenie Bouchard or Li - her pursuit of a maiden grand slam title will be hard to halt.
''I'm so happy and pleased, especially that I beat one of the best players in the world,'' Radwanska said of downing a foe with whom she shares a frosty relationship. ''I'm very happy that I made my first semi-final here.''
She does so in something of an unconventional year. The last time none of the top three women's seeds made the semi-finals here was 1997, when fourth seed Martina Hingis was joined in the last four by Mary Jo Fernandez (14), Amanda Coetzer (12) and the unseeded Mary Pierce.
The 2014 championships mark the first time in the Open era that neither the men's or women's defending champion has reached the last four here, and the first at any slam since Steffi Graf and Yevgeny Kafelnikov lost in the last eight at the 1997 French Open.
Radwanska had been on the wrong side of a 12-3 record against Azarenka, but among her many tennis talents is a knack for problem-solving. She worked over Azarenka as if the court was a board game to be traversed one square at a time.
''It's hard to play someone I lost [to] so many times before, [but] on other hand, I really have nothing to lose,'' she said. ''She was defending the title, not me. I was really trying to play my best tennis, go for every shot.''
Her approach was underpinned by the knowledge she had been to the quarter-finals here for the last three years, and it was time to take the next step. She takes steel from a semi-final loss to Sabine Lisicki at last year's Wimbledon, 9-7 in the third.
The Pole's tennis is a delight, caressing the ball to all corners, often from such a crouched stance that her backside almost brushes the court. She reads the play like a fortune teller; perhaps unkindly, Azarenka called it guesswork, yet to her shrieking frustration Radwanska was regularly two steps ahead of mind and body.
''I think something that you practice for so many years. Of course, maybe I was born with that,'' Radwanska said.
Azarenka bemoaned being too predictable, even stubborn in her refusal to adjust in the way her opponent did without thinking.
Radwanska's recovery from seemingly hopeless positions within points at times took the breath away, most notably a forehand volley at full stretch and ankle height, with the ball already past her, that left Azarenka beaten and agog at the net. Pam Shriver observed that there is a Genie on one side of the women's draw (Bouchard), and a genius on the other.
Cibulkova has played Radwanska six times for just one win, but two meetings last year were instructive of her growing capacity to put mishaps behind her. In Sydney just over a year ago, Radwanska wiped her 6-0, 6-0 in the final, yet in California in July, Cibulkova exacted revenge to claim her sole title of the year.
''You just have to … go against it, to be stronger than what happened before,'' Cibulkova said. ''So Wawrinka, he beat Djokovic last night. There was something also what happened to me in the past.''
The shortest woman (at 161centimetres) in the top 50 plays big tennis, giving the ball a wallop and bringing an intensity and fight to each contest; she calls this ''my gift''. She knows bringing a surprise to the table will increase her chances of adding to the catalogue of upsets.
''If you play against the best players you cannot do the same things all the time, you have to change sometimes the tactic. Today I bring my backhand down the line … it's something little bit new in my game.''
Cibulkova has been to the semis of a grand slam just once, at the French Open five years ago; it seems like a distant age. And the Slovak feels a more mature, experienced and rounded player to the 19-year-old she was then.
On Wednesday, she didn't give Simona Halep even a hint of a sniff in a 6-3, 6-0 win, but knows she won't have it so easy against Radwanska, who thinks they first met on court aged nine or 10 in one of the many junior tournaments they contested throughout Eastern Europe.
Both are 24, and confident their time has come.