She led 4-0 in the third set but had to hold her nerve as the five-time major winner refused to give in.

The Russian, seeing the match slip away from her, had made the Australian wait for seven minutes between the second and third sets as she took a bathroom break, and was booed by the crowd on her return. If it was a ploy to put Barty off, it didn't work.

In the end, Barty's variation proved highly effective against the far more seasoned player.

From the outset she deployed a range of tools to try and undermine Sharapava’s power. She leaned heavily on the slice backhand, ventured to the net on occasion, utilised more top spin than Sharapova and endeavoured to run her around with angles.

Far less subtle, her opponent may as well have had a sledgehammer in her hand.

Barty is no lightweight from the back of the court either, though, and when she found her range on the forehand side and began dictating terms, the momentum all of a sudden turned in her favour.

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Sharapova’s vulnerability on serve had been apparent when she struggled with the sun in her eyes at the southern end of Rod Laver Arena, and it became more brittle as the Australian broke her four times in a row to take the second set and race to a 4-0 lead in the third.

Her uncertainty obvious, Sharapova was called for a time violation for taking too long to serve. She managed to avoid dropping serve for a fifth succcessive time and then clawed her way back by breaking Barty immediately and closing the gap to 4-3.

Barty then had to show resilience to wriggle out of trouble when Sharapova had two points in a row to level the set at 4-4.

That window closed on Sharapova, and Barty did not allow it to be reopened.