When a young player is pitted against an opponent such as world number one and four-time major winner Iga Świątek, you can understand why they may feel as though they have nothing to lose.

Nineteen-year-old Linda Nosková has previously adopted that attitude when facing higher-ranked players and occasionally it has worked, resulting in an upset win.

But the 50th-ranked Czech knew she did not have to follow such as carefree approach when she played Świątek in the Australian Open third round on Saturday night.

Walking onto Rod Laver Arena, Nosková had full confidence she could beat the Pole and almost two-and-a-half hours later she did just that, pulling off the biggest upset so far this tournament.

"I know my game, I know that I have improved a lot in the last year-and-a-half," Nosková told the media after defeating Świątek 3-6, 6-3, 6-4.

"I just believed [in] my game tonight. I just really wanted this win because I didn't really come to that court with the thought of, 'I have nothing to lose'.

Świątek is the fourth top-10 player Nosková has defeated during her young career, but she admits she has not always had the self-belief she now enjoys.

"A lot of times I have played a top-10 player … I have actually nothing to lose and I'm just going to go there and try to play my best, and we'll see how it goes," she said.

"A few times I have beaten a great player, but it was maybe like a fluke or something like that."

Prior to making her Australian Open debut this fortnight, Nosková – who reached a career-high 40 on the WTA rankings last year – had only previously won two matches at the majors.

But reaching two finals in 2023 and making the last four at the Brisbane International earlier this month has helped build Nosková's confidence.

"I just know that when I'm going to be aggressive, I can play with anyone," she said.

"Obviously, there will be matches when I will not play my best. But tonight, especially when I warmed up, I was feeling pretty good."

For Świątek, the third-round loss adds to an inconsistent showing at the Australian Open since she first contested the major in 2019.