Postpublished at 00:44 Greenwich Mean Time 6 January 2018
Here's a cheerful stat for you...
S Marsh 98*, M Marsh 63*
Khawaja 171 - Crane's first Test wicket
England take two wickets in day
M Marsh overturns lbw on 55
Khawaja adds 188 with Smith (83)
Day five starts at 23:30 GMT
Australia lead five-match series 3-0
Jack Skelton and Amy Lofthouse
Here's a cheerful stat for you...
Stuart Broad's just bowled a delivery with the new ball that has reached Jonny Bairstow at about ankle height. Bodes well.
That's better, a proper effort ball from Broad, short and well directed, and Smith yanks his head out of the way.
Simon Mann
BBC Test Match Special commentator
Khawaja really got tucked up by that one. His gloves were high but he was trying to leave it.
There's a man out on the hook for Stuar Broad, which imple Usman Khawaja is going to get some short stuff.
Oh, and he is! Broad bangs the ball in and gets it rise up on Khawaja who, actually, doesn't play it well at all. He gets caught between hooking and leaving and ends up getting a sharp rap on the gloves, but the ball balloons up in the air and ends up short of the fielder. Broad goes short again and Khawaja, expecting it, rolls his wrist on a pull shot.
Michael Vaughan
Ex-England captain on BBC Test Match Special
We are watching greatness with Steve Smith. It's an English mentality to nit pick over his technique and how he can struggle against the swinging ball. But you don't get to 6,000 Test runs this quickly without being a great player.
Khawaja 111, Smith 71
James Anderson goes a touch fuller, trying to get Smith to miscue one, but he's having none of it. He jabs his bat down and flicks his wrist to turn the ball past two fielders and away through mid-wicket. It's good running, too, Smith urging Khawaja to turn quickly and secure a third.
It's as flat as a pancake out there, both in terms of the wicket and England's energy levels. Khawaja cobbles another single away to end the over.
The police at the SCG today have donated their day's wages to the McGrath Foundation, which is a lovely touch.
The drinks are off the field, and it'll be James Anderson to continue to Steve Smith.
Stephan Shemilt
BBC Sport in Sydney
Pink hats for the police.
Andrew Samson
BBC Test Match Special statistician
That's the 150 partnership and takes the career average of these two batting together to 71.8.
Four! Stuart Broad helps Usman Khawaja celebrate his century by gifting him a short delivery that's going whizzing down leg, and Khawaja gets a nibble on it to help it to the boundary. That also takes Khawaja to 2,000 runs in Tests.
Broad goes straighter to Khawaja and the Australia number three holds his bat high above his head. Over done, and it's time for drinks.
Text 81111
It amazes me that we don’t spear more yorkers at Smith’s leg stump. A leg slip, a fine leg and a man just in front of square would give the bowler the necessary protection, whilst forcing Smith to stay more leg side. It also makes him reach across that bit more to protect his off stump in that ‘corridor of uncertainty’. This is where we have perhaps missed Wood but Broad is a good exponent too.
Mike, London
Trail by 113
Nothing. Nada. Not a sniff in this pitch for James Anderson, who bowls some line and length stuff to Steve Smith. The ball doesn't move an inch off the pitch and Smith, wandering across his stumps, lets it fly through to Jonny Bairstow.
A maiden. Anderson looks more than a touch jaded.
James Anderson has a shiny red cherry in his hand as he and Joe Root briefly discuss tactics.
He's got Steve Smith in his sights. Although at this stage, England must be seeing Smith in their sleep.
#bbccricket
Richard Harris: I’m off to bed. When I wake up in 7 hours I fully expect Steve Smith to still be batting.
Steve Smith gives himself a running commentary when he's batting. Every false shot he plays, or if he doesn't quite middle a ball, leads to him furiously admonishing himself and practising the shot until he gets it right. He works a single before Usman Khawaja comes forward to meet a full delivery from Tom Curran and almost loses his balance.
It's second new ball time...
Dan Norcross
BBC Test Match Special
There has not been a hint of a sniff of a whiff of a wicket.
Trail by 115
Good reactions from Mason Crane as Usman Khawaja tries to plonk a single back past him, and Crane gets both hands down to keep Khawaja wary. Joe Root, standing at slip, doesn't look particularly happy with life at the minute. He watches Khawaja nurdle a single, before bringing in Crane and Jonny Bairstow for a chat at the end of the over.
#bbccricket
Mark: England's total that they seemed all so happy with, is of course now looking to be wholly inadequate. No one scoring 100, a few starts and not much better and a few important failures expose English batting again to be lacking. Looking like 4-0 unless Smith out soon.
A bouncer from Tom Curran first up, but it's called wide, much to the delight of the crowd. There might be a touch of extra bounce there for Curran, but Steve Smith drops his hands and slides an easy single away.
Curran mixes up his lengths nicely, going full to Usman Khawaja, but the centurion gets up on tiptoe and blocks.
Joe Root might have just realised he gets a nice new ball in three overs time. Tom Curran is going to replace Stuart Broad.