One seed, one qualifier, one teenager and one player who had never won four matches in a row before.

The top half of the Australian Open women’s singles draw has been blown open by a series of shock exits, leading to a finalist very few would have predicted.

One of China’s Zheng Qinwen, Ukraine’s Dayana Yastremska, the Czech Republic’s Linda Noskova or Russia’s Anna Kalinskaya will reach Saturday’s showpiece event at Melbourne Park.

Teenager Noskova and qualifier Yastremska meet in the quarter-finals at 12:00 local time (01:00 GMT) on Wednesday, before 12th seed Zheng plays Kalinskaya at 19:15 (08:15 GMT).

BBC Sport introduces the four women who have a shot at a surprise triumph.

Age: 23 Nationality: Ukraine World ranking: 93

Seeded players have been falling regularly over the past nine days – and Yastremska has been responsible for taking out three of the top 32.

She started by beating Wimbledon champion Marketa Vondrousova, earned another straight-set win against unseeded Varvara Gracheva and then ousted American 27th seed Emma Navarro.

Sticking to a bold style which complements her heavy forehand, Yastremska further cleared the way by knocking out former champion Victoria Azarenka in the last 16.

Yastremska reached a career-high 21st in the world in January 2020 but, because of a five-month absence because of a doping ban which was lifted and the effects of the war in her country, she has dropped down the rankings.

Now Yastremska is the first qualifier to reach a Grand Slam quarter-final since Emma Raducanu – who famously went on to win the 2021 US Open.

“A lot of things affected me, and because of that I couldn’t really play like I wanted,” she said.

Age: 19 Nationality: Czech Republic World ranking: 50

A year ago, Noskova lost in the first round of qualifying at Melbourne Park.

Now she is aiming for a place in the semi-finals having caused the shock of this year’s tournament by ousting world number one Iga Swiatek.

While a host of WTA stars have emerged from her nation over the years, Noskova says American 23-time major champion Serena Williams is her idol.

“When I was younger, I didn’t really watch tennis as much as my parents or the people that were around it a little more,” she said.

“But when I got into it, I was a big fan of Serena. I always probably will be. I like her style a lot.”

Noskova puts her rapid rise into the world’s top 50 down to working on building a strong service game.

“My game is to be aggressive almost all the time, especially at the right times. I just work on that daily just to improve the spots where I hit it,” she added.

Age: 21 Nationality: China World ranking: 15

Zheng is the only one of the four quarter-finalists to have reached the last eight of a major, but says she is unsure if it is a “big benefit or not”.

After her third-round win, there was a wholesome moment which could provide added inspiration for Zheng – an aggressive baseliner with a hefty serve – to go all the way.

During her post-match media duties, she was standing in front of a camera when Li Na – the trailblazing Chinese star who won the 2014 Australian Open – sneaked up and playfully tapped her.

Zheng has watched Li’s famous Melbourne victory “more than 10 times” – now she is looking to emulate her by becoming the second Chinese woman to reach the final.

Zheng, who reached the US Open quarter-finals last year, revealed it was the first time she had properly met her idol.

“She said to me ‘don’t think too much, just keep simple’,” said Zheng, who lives and trains in Barcelona.

“That’s what I’m trying to do. If you really focus on the basic things, you will show good things in the tennis.”

Age: 25 Nationality: Russia World ranking: 75

The daughter of professional badminton players, it may not be surprising that Kalinskaya ended up picking a racquet.

Unheralded but a consistent presence between the world’s top 50 and 100, she has broken new ground in Melbourne.

Beating former US Open champion Sloane Stephens in the last 32 meant Kalinskaya won three Grand Slam matches in a row for the first time.

She extended that run with a straight-set victory over Italian 26th seed Jasmine Paolini – the first time she had won four main-draw matches in a row at a tour-level event.

One of the key factors behind Kalinskaya’s success is the stability she has with coach Patricia Tarabini.

“We have been together for four and a half years, so I trust her a lot. She helps me outside of the court and inside as well,” said Kalinskaya.

“It’s very important to have this connection because when you have a tough moment, you need someone who can understand you without any doubts.”