Preview: Rafael Nadal lines up against exciting young prospect Stefanos Tsitsipas Thursday as he targets a fifth Australian Open final as form player Petra Kvitova looks to extend a 10-match win streak.
In Day 11 of action at the opening Grand Slam of the year, one of the men's finalists will be decided and both the women's.
Nadal has blasted through the draw without dropping a set, but Tsitsipas could be a tougher proposition after he pulled off the win of his life to knock out Roger Federer in four sets in the last 16.
The Spanish second seed, who plays the night match, is wary of the new Greek star, who he called "one of the best players in the world".
But he also declared his own time was not yet up as he chases an 18th Grand Slam title.
"They can wait a little bit," said Nadal of the new kids on the block. "But looks like they don't want to."
Seeded 14, Tsitsipas has plenty of respect for the world number two but is also surging with confidence at his best Grand Slam ever.
"I feel like I can do something good against him," said the 20-year-old.
The second men's semi-final, between six-time winner Novak Djokovic and Lucas Pouille, who is in his first last four match at a major, will played on Friday.
Two-time Wimbledon champion and eighth seed Kvitova faces tournament surprise package Danielle Collins, who stunned world number two Angelique Kerber on her way to her first Slam semi.
The unheralded American has adopted an aggressive approach during her campaign and is looking forward to meeting Kvitova, who beat her at the warm-up Sydney International in three tight sets.
"She's an incredible champion, has gone through a lot," Collins said, referring to the knife attack on Kvitova in December 2016 that almost derailed her career.
"We had a really great battle a couple weeks ago, one of the best matches I've played and I didn't even win. So I'm very familiar with her."
In the second women's semi-final, US Open champion Naomi Osaka takes on dangerous Czech Karolina Pliskova, who sensationally bounced back from 5-1 down in the third set to knock out Serena Williams in the last eight.
The Japanese fourth seed is looking to win back-to-back Grand Slam titles and is expecting a testing encounter from the never-say-die seventh seed.
"She's really tough to play. Like, I can barely read her serve, so it's very difficult for me," she said.
With inputs from AFP