“I didn't have many chances in the third set set, I was a bit mentally down,” Pliskova said. "Then suddenly I got a chance too. That's how it is in tennis. You need luck, of course, because this is I think not happening often, maybe once in life.
“But I went for it. I just said, ‘Like whatever. Maybe this can be over, but let's just try this game’.
“I was with the wind, which kind of helped me little bit. I just went for my shots. She got a little bit shaky in the end so I took my chances and I won."
Having wrested control of the match in the second set, Serena was looking increasingly sharp with her footwork and movement in the third – beginning to truly hurt Pliskova with the force of her shots.
Williams played a forehand return winner at full stretch to break for 3-1 – following that with a stare down the court for good measure – and then unleashed three consecutive aces to hold in the following game.
When she extended her lead to 5-1 by crushing an inside-out forehand return winner, there was nobody inside Rod Laver Arena, or watching on TV, or following along on social media, who could foresee any result other than Serena closing out victory to set up a tantalising semifinal against Naomi Osaka – a US Open final rematch.