Serena Williams' bid for a record-equalling 24th Grand Slam title was brought to a halt in sensational style at the Australian Open on Wednesday by Karolina Pliskova, but fellow former champion Novak Djokovic cruised into the semifinals.
The American great had beaten world number one Simona Halep in the fourth round but folded against the tall Czech seventh seed, who saved four match points before winning 6-4, 4-6, 7-5 under the hot Melbourne sun.
Her reward is a clash against Japan's Naomi Osaka for a place in the final after the Japanese fourth seed brutally swatted aside the injured Elina Svitolina 6-4, 6-1.
World number one Djokovic enjoyed an early night when courageous Kei Nishikori retired with a thigh strain when losing 6-1, 4-1 after going through three five-set epics during the tournament.
It kept the Serb's bid for a record seventh Australian title on track and he will now meet French 28th seed Lucas Pouille, who beat power-serving Canadian Milos Raonic 7-6 (7/4), 6-3, 6-7 (2/7), 6-4 to make his first Slam semi.
It was a gut-wrenching defeat for Williams, who battled back from a set down and was leading 5-1 in the third and serving for the match, only to throw it away with some wild shots as frustrations bubbled to the surface.
"There's nothing I did wrong on those match points. I stayed aggressive. She just literally hit the lines on some of them," said the dumbfounded 37-year-old, who rolled an ankle but refused to blame it for the defeat.
Since returning last year from giving birth, Williams has made four unsuccessful attempts to match Margaret Court's long-time standing 24 Grand Slam titles, and the wait continues with the French Open in May her next chance.
"The big picture for me is always winning," she added. "I'm not going to sit here and lie about that. It hasn't happened yet, but I feel like it's going to happen."
For Pliskova, it is only her third semifinal at a major.
She made the last four at Roland Garros in 2017 and the US Open a year earlier, where she beat Williams before losing the final to Angelique Kerber.
"I was almost in the locker-room but now I am standing here as a winner. It is a very good feeling," she said after depriving Williams of a US Open final rematch with Osaka.
Asked about facing Osaka next, Pliskova replied: "She's dangerous but nobody is more dangerous than Serena."
A focused Osaka rolled past Ukraine's Svitolina, who was troubled by neck and shoulder problems.
Despite the Ukrainian suffering, it was nevertheless a serious statement from the steely-eyed Osaka, who was playing the sort of tennis which drove her to the US Open title.
"I tried to be consistent, it's unfortunate that she got injured but playing against her even when she was injured was still really tough," said the 21-year-old.
"I just had one goal, to try as hard I can and not get angry. I didn't do that really well in the last two rounds and I did that today so I'm really happy with the way I played."
The win ensured she became the first Japanese woman in the final four since Kimiko Date in 1994.
Djokovic, who is targeting a 15th Grand Slam title, endured his own tough fourth round showdown with Daniil Medvedev and said he was glad to get off the court early.
"As they say, this is exactly what the doctor ordered for me after the match two nights ago," he said. "Not to spend too much time on the court.
"I've had plenty of matches so far this year and I am in another semifinal and I will do everything to get ready for that one."
Pouille had never won a match in Melbourne before this year but has recruited 2006 Australian Open champion Amelie Mauresmo to his team and said it was paying off.
"I started a new adventure with my team, with Amelie. I enjoy being on the court again and that is the most important," he said.
Quarterfinal results (prefix denotes seeding): Men's singles: 28-Lucas Pouille (FRA) bt 16-Milos Raonic (CAN) 7-6 (7/4), 6-3, 6-7 (2/7), 6-4; 1-Novak Djokovic (SRB) bt 8-Kei Nishikori (JPN) 6-1 (retired).
Women's singles: 7-Karolina Pliskova (CZE) bt 16-Serena Williams (USA) 6-4, 4-6, 7-5; 4-Naomi Osaka (JPN) bt 6-Elina Svitolina (UKR) 6-4, 6-1.