Serena to "keep soldiering on" after epic Pliskova comeback
Leading 5-1 in the deciding set, and with match point at 40-30 on her own serve, Serena Williams looked certain to reach the semi-finals of the Australian Open.
But Karolina Pliskova had other ideas.
Cue a career-defining comeback, to end Serena's hopes of adding to her 23 Grand slam titles in Melbourne.
The turning point... a foot-fault from the world's greatest female player.
After the rare foot-fault at match point, Serena was wrongfooted by her Czech opponent on second serve.
The American turned her ankle as she netted a forehand.
Pliskova sensed her chance.
The Czech player won four straight games, saving three match points in the process.
She then broke to love to go 6-5 up, and raced to 40-0 to bring up three match points.
Williams saved the first two, but Pliskova would not be denied.
She went on to win 6-4, 4-6, 7-5, reaching the last four in Melbourne for the first time, and ending the American's hopes of this year claiming an eighth Australian Open title.
"I did everything I could"
Williams refused to blame her ankle twist for her defeat, instead praising Pliskova for her comeback.
"My ankle seems to be fine. I usually don't know until the next day. I think she just played lights out on match point.
"I didn't do anything wrong. I stayed aggressive. She just literally hit the lines on some of them. One she hit an ace, unreturnable serve.
"I literally did everything I could on those match points. I can't say that I choked on those match points. She literally played her best tennis ever on those shots." - Serena Williams on Karolina Pliskova
The defeat means Williams remains without a title since her 2017 Australian Open triumph, the last tournament she played before giving birth in September 2017.
It also means she stays stuck on 23 Grand Slams, one behind the all-time record held by Margaret Court.
She added, "I mean, the big picture for me is always winning. 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.
"Just keep taking it one match at a time, just keep soldiering on, I guess."
For Pliskova, still seeking a first Grand Slam title, it was "best comeback ever so far in my life".
She added, "Before the match, this time I really believed.
"I know she's the greatest ever, but I beat her before. She was No.1 at that time. I knew I was going to have my chances. But I had to play well."
It was the former world number one's second win over Williams, her first coming in the 2016 US Open quarter-finals.
Now she faces Naomi Osaka, the woman who beat Williams in last year's controversial US Open final.
The Japanese star beat Elina Svitolina 6-4, 6-1 to reach her first Australian Open semi-final.
Osaka edged a tight first set but moved clear in the second as Ukraine's former world number one struggled with a shoulder injury.
The other semi-final sees Pliskova's Czech Fed Cup team-mate Petra Kvitova go up against the tournament's surprise package Danielle Rose Collins.
The 25-year-old American is a rarity in tennis in that she did not turn pro until the age of 22.
The University of Virginia graduate had an 0-5 record in Grand Slam main draw matches before causing a string of upsets in Melbourne.
World number 35 Collins has beaten three seeded players, including a 6-0 6-2 demolition of former champion Angelique Kerber, on her way to the last four.
She will be the underdog yet again when she meets two-time Wimbledon champion Kvitova.
The 28-year-old left-hander is enjoying her best run at a Slam since suffering tendon and nerve injuries to her racket hand when a knife-wielding intruder attacked her in her home.