The Czech seventh seed pulled out of the warm-up Adelaide International last week with a hip injury and her court movement appeared to be impaired in Melbourne.

She lost her opening service game and never got back in the contest as 93rd-ranked Yastremska took control on John Cain Arena, surging through the first set in just 31 minutes.

Vondrousova, who beat Australian Open sixth seed Ons Jabeur for her breakthrough at the All England Club in July, was broken again at the start of the second set and there was no way back.

“Today was a really nice game,” said Yastremska, who hit 26 winners to Vondrousova’s five.

“I was a little bit nervous, but I just tried to enjoy myself. Today, I felt huge support from the crowd.”

It was her fourth career win over a top-10 player, most recently beating then-world No 3 Barbora Krejcikova in Dubai in 2022.

Yastremska, whose best showing at Melbourne Park was a third-round appearance in 2019, will next play France’s Varvara Gracheva, who is unseeded.