Cameron Green joins double centurion David Warner in retiring hurt on day two of the Boxing Day Test at the MCG.
Warner became the second man, after England's Joe Root, to score a double century in his 100th Test, going off immediately after reaching the milestone with cramping and heat exhaustion.
Green, meanwhile, was hit on the right index finger while batting. The finger was bloody and swollen as he left the field late in the day, casting doubt on his ability to bowl in the second innings and back up his maiden five-wicket haul from the first innings.
Look back at all the action in our live blog, check out the live scorecard, or tune in to our live radio coverage from the MCG.
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Stumps: Australia 3-386 (Head 48, Carey 9)
By Simon Smale
Well that was a terrific day for Australia and David Warner.
The conditions made it tough, but certainly made for a stunning backdrop to a performance for the ages from David Warner.
He becomes the first Australian to score a double century on the occasion of his 100th Test.
There are issues for Australia though.
Warner looked in a terrible state when he retired hurt, through heat exhaustion most likely, as he was helped from the ground.
Then Cameron Green left the field with a knuckle that was, if not broken, then very badly bruised.
Both could, in theory, return tomorrow and pile more pain on South Africa's wilting bowling attack that looked to be in just as much strife as it was possible to be in.
Just two wickets fell today - both of them from Australian errors rather than good bowling, although the good bowling that was done by the South Africans was not rewarded as balls flew past the outside edge and narrowly missed the stumps.
The weather forecast for tomorrow is for there to be some rain about at times, but it will be cooler and hopefully we'll still be able to get plenty of play in as Australia pushes for an innings victory.
Thanks for being with us today, from myself and Jon, good evening.
91st over - Rabada to bowl the last of the day
By Simon Smale
Four! Crack goes Alex Carey and he smashes that through the covers for another boundary. Bit wide from Rabada.
Fuller, straighter and Carey drives down the ground only for Rabada to flick the ball up off his boot and save a boundary.
Carey clips the ball off his hip for a single.
Head defends the last.
Four! Head clips off his pads down to fine leg for another boundary that moves him to 48 off 48.
And that's stumps.
90th over - Maharaj subs in for Ngidi
By Simon Smale
OK, so Maharaj has been called upon, mostly because there is nobody else I'd expect, and will have to bowl the rest of the 90th over - five balls in fact.
Head is forward, defending the first.
Will Maharaj keep the South Australian quiet where nobody else has been able to?
So far, so good through three balls, all dots, all defended by Head.
Head creams that to mid off for no run - great shot for no run.
Four! Head sweeps for four more runs to end the over on a positive note.
He moves to 44 with about 4 minutes remaining in the day's play. Time for a cheeky 50?
90th over - Another change, Lungi Ngidi comes in
By Simon Smale
A single for Carey off the first ball, comfortably taken square on the leg side.
Now Ngidi is down with cramp and Richard Kettleborough has to help him out. As a Yorkshireman, I doubt Mr Kettleborough has ever heard of cramp before today - and certainly never been felled by it.
Ngidi can't continue. Goodness, they're falling like flies out there.
89th over - Bowling chance Kagiso Rabada comes into the attack
By Simon Smale
Head cuts at a short, wide loosener and Travis Head runs three to deep cover.
Not great from Rabada - that's probably why he hasn't been given the new ball in this innings.
Two slips and a gully in place as Rabada finds his line and Carey defends the next couple.
Quick single as Carey cuts and gets an inside edge that falls to short square leg.
Good bouncer! Head fends it in the air off his glove but there's no fielders there and the ball falls safe. Good ball, a real nasty one to handle for Travis Head.
Captain grumpy isn't impressed
By Simon Smale
It's only a finger - get back out there.
- Alan Border
That finger is worth over $3 million to be fair.
But yeah, I can't imagine Allan Border being overly impressed.
88th over - Jansen continues
By Simon Smale
Head defends the first couple and then cuts to point for a single,
He moves to 37 off 39 - just a standard Travis Head run-a-ball innings then.
Carey cuts and misses, looking to advance his score off the 2 he's managed from 12 balls so far.
Well wide outside off to end the over.
Spidercam update
By Simon Smale
So I've done some research and yes, it appears that spidercam tried to kill Anrich Nortje.
No wonder he's been taking out Australian knuckles like flies since then.
Apparently, the camera came off a bit worse for wear.
87th over - The Uitenhage express, Anrich Nortje steams in
By Simon Smale
One leg bye first up to get Head off strike.
Carey is being pretty watchful to this pace battery from Nortje and fends whenever he is threatened.
86th over - Marco Jansen continues
By Simon Smale
Head takes a single, while Nortje gets some helpful advice from the very well watered supporters on the boundary.
Carey drives to cover where the ball is fielded.
Nortje is being encouraged to drink his water and as he drains a bottle of water, gets a standing ovation by those in Bay 13.
Carey nails another drive straight to the fielder.
Arrest spidercam!
By Simon Smale
Did you see the Spidercam knock over Nortje? Shameful!
- OneBlessedMama
I actually missed this... but am now going to trawl social media for it.
85th over - Nortje to bowl his last two deliveries
By Simon Smale
Alex Carey the new man, in the middle with Australia only three down, such is the quirk of Test cricket.
Two runs, straight down the ground and that's a lovely shot to get off the mark to a ball that was slightly overpitched.
Bouncer into the body of Carey, who tries to hook but only manages to hit himself on the thigh.
Cameron Green retires hurt
By Simon Smale
Uh oh, Cameron Green is being walked off the ground with a very sore looking knuckle and Australia are being dismissed conventionally, but are losing men out there.
Cam Green being out of things is very bad news, given his importance with the ball after Starc's injury.
Suddenly, the bowling stocks look a bit thin and Australia will need every single run they can get here.
85th over - Nortje continues
By Simon Smale
Head defends into the off side for no run - 139kph from Nortje.
Head flicks off his pads to mid wicket for a single.
Nortje just stretches out his calves a bit at the end of his run up, three slips and a gully wait, as well as the bat pad, and Green defends a 145kph delivery into the off side.
Green wears a rising bouncer on the glove and that looks like it might be a bit sore.
Oh dear, the glove is off and the finger is bleeding.
Just got trapped between handle and the ball travelling at 145kph and that will be sore.
He'll need a bit of time here, Cam Green, plenty of time actually, Green is going to go off.
84th over - Jansen will have another one
By Simon Smale
Head continues where he left off and clips off his pads for a single to deep backward square leg.
Jansen sends the ball across Green's body and earns some cheers of encouragement from the men behind the bat, two of them in the slips and a gully.
Green leaves the next on length and fends the one after into the off side for no run.
Wide down the leg side from Jansen. Silly sort of ball to bowl really, the Proteas need to make these batters play with this new ball.
Four! Lovely shot from Green! Driving to the vacant long off boundary.
83rd over - Nortje will steam in again
By Simon Smale
Green is not Travis Head so defends solidly to another rapid delivery from Nortje, angling in to Green. It was actually under 140kph, that ball.
Now Green drives and picks out the fielder at wide mid off.
Yorker at 145kph and Green's done well to dig that one out.
CLOSE! Zondo at bat pad dives forward and just can't get to the ball that looked off the bat in time.
Green fends the ball to mid on, no run.
Green gets off the mark with a couple of runs to backward square leg.
They're gunna have more drinks because of the heat - and that's probably fair enough.
82nd over - Marco Jansen gets the new ball at the other end
By Simon Smale
Good decision for me, he's been good without luck, 0-39 from 12 overs so far this innings.
Outside off, the ball swinging a bit away after pitching. No shot taken though by Travis Head.
SIX! WHAT A SHOT! Jansen has strayed down leg and Head has smashed that over the backward square leg boundary for six runs! Wowza.
BEATEN! What a response! Moved away a touch just off the seam and Head was left prodding at air.
That ball died outside off, going through to keeper Verreynne on the bounce.
Bay 13 are keeping entertained by copying Rabada's warm up behind him - and I think he's enjoying it too.
Four! He's gone again to that leg-stump delivery, Head this time clips it to wide mid on.
Second new ball taken - Anrich Nortje has it
By Simon Smale
This is a big moment in the game.
South Africa need wickets and they have the fastest man in world cricket (sorry Mark Wood, it's true) with the ball in hand.
Nortje to Head, bouncer at 145kph that Head gets under.
Head defends a fuller ball back down the pitch, slower at 142kph that one.
And yes, I am obsessing a bit about the speed, but I think it's warranted.
Edgy from Head out to deep point and it's a single.
Cam Green is the new man in and he'll have to get his eye in pretty quick.
BEATEN! What a ball - Cam Green played down the line and that's missed the outside edge by not very much at all. Perfect length and a decent line.
Three slips in place - so they've added one for Green, bat pad is there too, Nortje fires the ball down outside off stump.
Outside off again from Nortje, they need to target the stumps a bit more I think and make the batters play their shots at least.
80th over - Maharaj continues
By Simon Smale
Second new ball is due next over.
Head is defending the first couple.
Four! Head cuts brilliantly and gets a boundary to deep square leg, Nortje was chasing hard and has cramped as he dived! Oh no! You'd think he'd be a prime new ball candidate for South Africa.
Head takes a single to long on.
Green defends back in his crease to end the over.
