Novak Djokovic beats Roger Federer in first men's semi-final
2019 champion Djokovic fights back to win first set tie-break
Serbian dominates from there to win 7-6 (7-1) 6-4 6-3
Federer needed medical timeout at end of first set
Dominic Thiem and Alexander Zverev meet in second semi-final on Friday
Watch highlights on BBC Two from 15:15 GMT
Garbine Muguruza & Sofia Kenin reach women's final
*Barty 5-5 Kenin
Nice angles from Kenin, who forces Barty wide. A loose backhand again from Barty... 30-0.
Another good rally which goes Barty's way as Kenin slumps one into the net. Then the Aussie launches one of those wild backhands over the baseline.
Kenin has an unforced error of her own. 40-30. Then Barty hooks ANOTHER backhand wide.
Barty 5-4 Kenin*
A big kick-serve from Barty brings up 30-0 and Kenin messes up the pick-up from the drop shot.
Another wild backhand from Barty follows but she holds comfortably.
Jonathan Jurejko
BBC Sport at Melbourne Park
Usually Garden Square, where day pass holders can lazily lay back in a deckchair and watch the Laver action on the big screen, would be packed for a match of this magnitude.
Today, because of the sweltering conditions, you can take your pick.
Image source, BBC SportThat's not to say there aren't plenty of Aussie fans cheering on their girl.
It's just they are sheltering from the sun under the trees which arc around the seating area.
Image source, BBC Sport*Barty 4-4 Kenin
Kenin moves into the net and puts away the slice volley. Barty then hooks one wide but Kenin lashes at the next one.
The American puts a second serve down the middle and follows it up with a careful forehand into the open court.
What are you thinking so far? Barty to come through or Kenin to pull off a shock? And let us know where you're following us from. Tweet #bbctennis or text 81111.
Barty 4-3 Kenin*
Barty's coach Craig Tyzzer is sporting a Liverpool FC cap. Trying to spread the winning mentality to Barty!
Barty 4-3 Kenin*
Nice movement from Barty who moves up to 30-0 and she gets lucky when Kenin pokes an awful volley into the net with the space open for her down the line.
Barty seals the hold with a pacey forehand.
*Barty 3-3 Kenin
An ice towel required for Kenin too...
Image source, AFP*Barty 3-3 Kenin
Kenin plays it short to take advantage and Barty then plants another backhand into the net.
Hmm.
Barty 3-2 Kenin*
Loose again from the Aussie. Back to deuce.
Barty cuts another forehand into the net but Kenin hooks a dodgy backhand of her own into the cords. Deuce.
Barty 3-2 Kenin*
She gets this backhand right though! A fizzing one from Barty hits the line.
A third break point.
Jonathan Jurejko
BBC Sport at Melbourne Park
If any two players can cope with these conditions then Barty and Kenin would be right up there.
Barty hails from Queensland and Kenin is from Florida. So they are well used to these conditions.
Having said that, Barty asked for an ice towel at the last changeover...
Barty 3-2 Kenin*
A 10th unforced error from Barty, whose backhand is still not working for her. It's that side which lets her down again as a slice falls into the net.
Barty looks at her racquet, confused. Deuce.
Barty 3-2 Kenin*
Double fault from Kenin after a successful challenge from Barty. The Aussie challenges again on a forehand and is successful, bringing up two break points.
Jonathan Jurejko
BBC Sport at Melbourne Park
The Australian Open heat stress scale has now hit the 4.0 mark. That means - if it stays like that, which it should - there will be an extended break between the second and third sets. If it goes that far of course...
Barty 3-2 Kenin*
Ace number three and four from Barty but her backhand is still causing some problems as another flies wide.
She adds a fifth ace to go 40-15 up and a sixth to hold. Fantastic serving!
Image source, AFP*Barty 2-2 Kenin
Barty goes deep on the forehand but Kenin reaches them both and forces the error. Another backhand from Barty goes astray and Kenin then pulls out a drop shot and a lovely lob.
An ace seals the hold to love. Very good from the American as well!
Barty 2-1 Kenin*
A nice one-two punch brings up 40-0 for Barty and Kenin's forehand falls over the baseline. A very good hold for Barty.
*Barty 1-1 Kenin
Nervy start from both players actually. Big day.
Barty responds with two aces in a row. Nice!
Image source, Getty Images*Barty 1-1 Kenin
Barty looks a bit shaky, she has had six unforced errors already and drags another backhand long.
We're on level terms.
Image source, Getty Images