An emotional Mirjana Lucic-Baroni has continued her remarkable run into the Australian Open semi-finals with a topsy-turvy 6-4, 3-6, 6-4 upset victory over number-five seed Karolina Pliskova.

It came 18 years after Lucic-Baroni’s only previous grand slam semi-final appearance.

The Croatian then spent many years away from the sport and later claimed she had been abused from early childhood by her father.

Lucic-Baroni will play six-time Open champion Serena Williams on Thursday for a place in the title match.

“I can’t believe it — this is crazy,” said Lucic-Baroni.

“God is good. That’s really all I can say.”

The world number 79 said one day she would open up fully about all the hardships she has endured before this unexpected late-career renaissance.

I know this means a lot to any player to reach the semis, but for me it is overwhelming.”

The 34-year-old took a medical timeout when trailing 3-4 in the final set against Pliskova on Wednesday, before returning to streak through the final three games in a match lasting one hour and 48 minutes.

Both players had plenty of trouble serving throughout, with the Czech dropping serve three times in the decider.

“It’s really tough,” Lucic-Baroni said. “I’m going to do my best to keep calm and recover.”

Serena on track for seventh title

Second-seeded Williams was rarely troubled against British ninth seed Johanna Konta, winning 6-2, 6-3 on Rod Laver Arena.

She dominated on serve, sending down 10 aces and losing only one service game compared to four breaks of her opponent.

Serena Williams celebrates winning her quarter-final match against Johanna Konta of Great Britain. Photo: Getty.

Williams also hit 25 winners to Konta’s 11, and she held her serve to love to finish the match in one hour 15 minutes.

The 35-year-old has won the women’s singles title in 2003, 2005, 2007, 2009, 2010 and 2015 — and now she must be the strong favourite a seventh title, with two unseeded players and one other seed left in the semi-finals.

In advancing to her 10th consecutive grand slam semi-final, she also completed the oldest Australian Open women’s last-four line-up in 40 years.

Before Williams takes on 34-year-old Lucic-Baroni, her older sister Venus, 36, will face fellow American CoCo Vandeweghe, a relative spring chicken at 25, in Thursday’s first semi-final.

“It’s really amazing. Thirty is the new 10,” said Williams, who labelled Lucic-Baroni’s revival as inspiring.

“I’m so proud of Mirjana. She’s been playing so well,” Williams said.

We played well over a decade ago. Oh my god, over two decades ago.

“No matter who wins, someone older than 34 will be in the final and that’s just great.”