MELBOURNE, Australia -- It's a quick turnaround for both Karolina Pliskova and Naomi Osaka, who clash just one night after their quarterfinal wins at the Australian Open.

But before they take the court, American Danielle Collins takes on two-time Wimbledon winner Petra Kvitova (Wednesday, 10 p.m. ET on ESPN2). Kvitova hasn't dropped a set on her way to her first major semifinal since 2014.

In the evening's only men's semifinal (Thursday, 3 a.m. ET on ESPN), world No. 2 Rafael Nadal will look to delay any further talk of the changing of the guard in men's tennis when he takes on Stefanos Tsitsipas.

How to watch

Day session

ESPN3 & ESPN+: Starting at 7 p.m. ET

ESPN2: Starting at 10 p.m. ET

Night session

ESPN: Starting at 3:30 a.m. ET

Full Day 11 schedule

Key storylines

Osaka seeking second straight Grand Slam final

Naomi Osaka looked dominant in her win against Elina Svitolina on Wednesday. Greg Wood/AFP/Getty Images

It was a breakout year for Naomi Osaka in 2018, but if her rivals were hoping for any semblance of a letdown, they might be waiting a long time.

Through to the Aussie Open semifinals after a dominant performance against sixth seed Elina Svitolina, Osaka needs just one more victory to make her second consecutive major final, and just two more wins to be the first woman to win back-to-back Slams since Serena Williams won four straight from the 2014 US Open to Wimbledon in 2015.

As well as Osaka as played, her opponent, Karolina Pliskova, is looking just as dangerous. The Czech No. 7 saved four match points against Williams before completing an astonishing comeback from 5-1 down in the third set.

Can Danielle Collins keep her dream run alive?

Danielle Collins is playing the best tennis of her life en route to the Australian Open semifinals. Fred Lee/Getty Images

She had never won a Grand Slam match before this year's Australian Open, but Danielle Collins has showed how much talent and fight she has in reaching the final four. The world No. 35 has wins over Julia Goerges, Caroline Garcia and Angelique Kerber, but faces another in-form player in No. 8 Petra Kvitova.

Kvitova has played some of her best tennis since the frightening knife attack she faced in 2016. Coming off a title at the Sydney International to start the year, Kvitova has not lost a set through five matches in Melbourne.

But in another Aussie Open tuneup in January, Collins pushed Kvitova to three sets in Brisbane, taking the opening frame in a tiebreaker, a match that has given Collins confidence.

"We had a really great battle a couple weeks ago," Collins said after her last match. "One of the best matches I've played."

Can Tsitsipas continue to upstage the Big Four?

Greece's Stefanos Tsitsipas celebrates his victory against Georgia's Nikoloz Basilashvili during the 2019 Australian Open. GREG WOOD/AFP/Getty Image

It was the victory over Roger Federer that made the world take note of 20-year-old Greek sensation Stefanos Tsitsipas. But now he faces another massive test.

Standing in his way is world No. 2 Rafael Nadal, who hasn't lost a set here so far. Nadal beat Tsitsipas twice in 2018 -- in straight sets at both the Canadian Masters and in Barcelona.

Some labeled Tsitsipas' breakthrough four-set win over Federer as a changing of the guard in men's tennis, but with Nadal -- and possibly Novak Djokovic -- still to come, the old guard isn't going anywhere yet.