Williams out with barely a whimper

back to her best. And Williams at her best is a terrifying sight.

But for a set and a half, Pliskova, the world No8, had been in charge, taking the ball early and hitting it flat to manoeuvre her way to a set and a break lead.

Yet as soon as she broke in that second set, Williams broke straight back and seemingly took complete control of the match. This was Serena on the march to victory.

“My mind was in the locker room,” said Pliskova. “It was tough because she was really playing well. I didn’t have many chances in the third set.”

The American then turned her ankle and the match was turned on its head.

The Australian Open is only the ninth event Williams has played since she had her daughter in September 2017. Trying to return to full fitness has been hard enough but that lack of matches has taken its toll on the once-ferocious Williams mindset.

“Next time I’m up 5-1 against anybody, whether it’s her or anyone, I just need to make sure I play lights out when I have match points,” she said.

“It’s little things like that I used to do, always do, that

I need matches to know that, ‘OK, this is when you go psycho, when you have match point’.” Pliskova will now face

Naomi Osaka – who won the US Open last year while Williams was still ranting at the umpire – after the Japanese beat Elina Svitolina 6-4, 6-1.

Meanwhile, Novak Djokovic says his abbreviated 6-1, 4-1 quarter-final win over an exhausted Kei Nishikori was “just what the doctor ordered”.

The No1 seed and six-time champion had been struggling with what looked like a sore back and hip in his fourth-round match and the thought of five sets with the dogged Nishikori was not to his liking.

But Nishikori had played five sets and more than five hours in his previous match and was feeling the after-effects. Landing heavily after a serve in the early stages of yesterday’s match, he hurt his right leg and threw in the towel in the second set. Djokovic now plays Lucas Pouille in the semis, the Frenchman beating Milos Raonic 7-6,

6-3, 6-7, 6-4.