As always you have a role to play so tweet us using #bbctennis and let us know your thoughts on this match and the tournament.

Rafael Nadal, a winner in 2009, is aiming for a fifth Australian Open final.

"When you face these young players, they are in permanent improvement," said Nadal. He's with confidence. He won a lot of good matches. It will be a tough one

"For me it's always the same: you're in the semi-finals of a Slam, you can't expect an easy opponent. Stefanos is one of the best players of the world. To have the chance to be in that final, I need to play my best and that's what I am looking for."

Image source, Reuters

Seeded 14, Stefanos 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 Tsitsipas.

"I felt very close to beating him in Toronto, though the score was 6-2 7-6. I remember coming back to the locker room and promising to myself I'm going to do much better against him next time."

Head-to-head record (Tsitsipas 0-2 Nadal)

2018 Nadal bt Tsitsipas 6-2 7-6 (7-4) (Toronto, hard)

2018 Nadal bt Tsitsipas 6-2 6-1 (Barcelona, clay)

Image source, Getty Images

First round: Beat James Duckworth (AUS) 6-4 6-3 7-5

Second round: Beat Matthew Ebden (AUS) 6-3 6-2 6-2

Third round: Beat Alex De Minaur (AUS, 27th seed) 6-1 6-2 6-4

Fourth round: Beat Tomas Berdych (CZE 6-0 6-1 7-6 (7-4)

Quarter-final: Beat Frances Tiafoe (USA) 6-3 6-4 6-2

Image source, Getty Images

First round: Beat Matteo Berrettini (ITA) 6-7 (3-7) 6-4 6-3 7-6 (7-4)

Second round: Beat Viktor Troicki (SRB) 6-3 2-6 6-2 7-5

Third round: Beat Nikoloz Basilashvili (GEO, 19th seed) 6-3 3-6 7-6 (9-7) 6-4

Fourth round: Beat Roger Federer (SUI, third seed) 6-7 (11-13) 7-6 (7-3) 7-5 7-6 (7-5)

Quarter-final: Beat Roberto Bautista Agut (ESP, 22nd seed) 7-5 4-6 6-4 7-6 (7-2)

Image source, Getty Images

Russell Fuller
BBC tennis correspondent at Melbourne Park

Unless the humidity rises then I think the roof has to be opened for the Nadal match.

The highest recorded temperature around this area today was 40C - it's expected the temperature might hit 44C on Friday.

Any of the junior matches and wheelchair matches on the outside courts will just not happen.

Jonathan Jurejko
BBC Sport at Melbourne Park

Image source, BBC Sport

Temperatures have reached almost 40C in Melbourne today - although not quite the record 43C that it reached in 2014.

It might be 7pm here but the heat is still intense and still close to 40C.

Even the Melburnians - along with, less surprisingly, tourists - have been desperately seeking shade and sunscreen.

Image source, BBC Sport

Image source, BBC Sport

You may well be waking up today to an icy / snowy scene in Britain but it is not the case out in Australia, here's our man Jonathan Jurejko out in Melbourne...

Hello and welcome along to BBC Sport's coverage of the first men's singles semi-final at the 2019 Australian Open.

I'm Michael Emons and I will be taking you through all the action in what promises to be a thrilling match between Stefanos Tsitsipas and Rafael Nadal.

We will also have live commentary on BBC Radio 5 live sports extra as well, so press the play button at the top to listen along.

What a shock it was on Sunday when 20-year-old Stefanos Tsitsipas knocked out six-time Australian Open champion Roger Federer...

Image source, Getty Images

...now the Greek youngster is aiming to reach his first Grand Slam final, but standing in his way is the power of Rafael Nadal, who has been in stunning form in this tournament - reaching the final four without even dropping a set.

Image source, Reuters

That is that for now.

Greek player Stefanos Tsitsipas faces number two seed Rafael Nadal at 08:30 GMT for a place in the men's final.

We will have live text commentary and BBC Radio 5 live sports extra commentary in just over 15 minutes so we won't be gone long...

It was a disappointing day for Britain's Andy Lapthorne and American partner David Wagner who were beaten by Australian pair Dylan Alcott and Heath Davidson in the quad wheelchair doubles final.

It started well for Lapthorne and Wagner before number one-ranked player Alcott led the fightback.

Image source, Getty Images

In the end, two-time Wimbledon champion Petra Kvitova had too much arsenal for surprise American semi-finalist Danielle Collins.

Kvitova will now face Osaka in her first Grand Slam final since the knife attack at her home two years ago.

"It means everything, finally I can make it deep in this major and whatever happens I'm very happy," she said.

Read the report here.

Image source, Getty Images

Australian Open finalist Naomi Osaka is asked about her feelings when Karolina Pliskova won the second set, she replies: "I kind of expected it a little because I've played her so many times and she has beaten me more than I've beaten her. I told myself to regroup and I managed to win.

"It's just experience playing matches like this. I was so scared serving second serves, I was like 'oh, my god, please' and somehow I made it so I guess that's experience.

"Thank you for cheering and I will try my best in the next match."

On the roof being closed: "I like the heat so I was kind of sad. When they have the roof open it's my time to shine."

On what she will do between now and the final: "I'm going to go to sleep and maybe after that I might walk a bit, perhaps not to be honest."

Image source, Reuters

So that's another final for the effervescent Naomi Osaka.

If you couldn't be bothered to scroll through every entry I have written to find out how she made it there, then I suggest you read Jonathan Jurejko's report.

Dennis Ethan: Both are big hitting Petra & Naomi, it will be small margins but I think the experience of Kvitova will see her through

Image source, Getty Images

Osaka hit an incredible 56 winners.

Kvitova will have to up her game because the US Open champion is playing at Serena levels.