Postpublished at 05:03 Greenwich Mean Time 5 January 2018
Ed Smith
Ex-England batsman on BBC Test Match Special
He has a very sprightly approach to the crease.
Warner 56, Khawaja 91*, Smith 44*
Smith rides luck in stand of 107*
Eng 346: Root 83, Malan 62, Curran 39
Cummins 4-80, Hazlewood 2-65
Day three starts at 23:30 GMT
Australia lead 3-0 in five-Test series
Amy Lofthouse, Jack Skelton and Saj Chowdhury
Ed Smith
Ex-England batsman on BBC Test Match Special
He has a very sprightly approach to the crease.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
Mason Crane has got a little bit about him. I like energetic actions; I like bowlers who get through the crease. He's very light on his feet - ballerina-esque.
Mason Crane whirls his arm over, going through the motions as Steve Smith settles himself in at the crease. Smith wants a single from the first ball but Usman Khawaja isn't interested. He eventually leans back and cracks the ball away for one.
Khawaja then shuffles his way out of his crease to work a single to end the over.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
Khawaja, like Vince, is one of the easiest on the eye. Today he has looked fabulous - he has looked effortless.
Steve Smith rolls his wrists on a couple of singles, before Usman Khawaja leaves, and leaves some more. These deliveries are going through low to Jonny Bairstow, who picks up one ball from just in front of his big toe. Another sedate over from Curran.
Ed Smith
Ex-England batsman on BBC Test Match Special
It drifted and turned quite sharply. Encouraging signs for Mason Crane here.
Oh! A big lbw shout from Mason Crane's first ball! Usman Khawaja gets trapped on the crease as he presses forward, and he's struck on the back pad. Joe Root comes over to ask about the review but Crane says he reckons it's going down leg.
Crane then has Khawaja wafting at a delivery that turns, and turns sharply. A no-ball brings a run, before Khawaja wallops a short ball away to the boundary. Tom Curran dives to stop it, misses, and rolls into the boundary rope in the process.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
It's tough going at the moment for England.
That's exactly what Joe Root has done - here's Mason Crane, replacing Moeen.
Stephan Shemilt
BBC Sport in Sydney
It's a bit like being at Wimbledon...
A bit of extra bounce from Tom Curran, as one rises up on Steve Smith, who pulls a face at the pitch. Smith then doesn't move his feet and the ball takes the outside edge, but it bounces past slip and he jogs an easy two.
Given Steve Smith's propensity for getting out to England debutants, I'd get Mason Crane on for a bit.
Hmm. Time for a change for England - here's Tom Curran, who dismissed Steve Smith in the first innings in Melbourne.
Andrew Samson
BBC Test Match Special statistician
Khawaja's fifty came off 107 balls in 141 minutes and contained four fours and a six.
Dan Norcross
BBC Test Match Special
Khawaja has not really looked in great nick throughout this series, but in this match he has dug in.
Aus 114-2
Usman Khawaja brings up his half-century with a six!
Some more lovely foot movement from the Australian number three as he comes darting down the pitch before lofting Moeen straight back over his head. The ball hangs temptingly in the air for a second, but there's enough on it to clear the ropes. Lovely stuff, and he raises his bat to an appreciative crowd.
#bbccricket
Ben Wire: Why is Moeen bowling?! What about Crane? Isn't that why he's there? And he's bowled on this ground before! Utter madness.
Trail by 239
Steve Smith, with his exaggerated movement, steps across and defends James Anderson's first few deliveries, before he hustles a single off his hip.
Anderson changes direction, going around the wicket to Usman Khawaja, and he squares him up a touch. Khawaja stays solid in defence, though, and pats away the rest of the over.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
I love batters using their feet. He made it look effortless.
Khawaja 45, Smith 4
Mitch Marsh is drinking an espresso up in the Australia changing rooms. A hipster version of the traditional energy drink. Big brother Shaun, sat next to him, looks a bit unimpressed.
Hello, that's four! Usman Khawaja goes for an early trot down the pitch and carves Moeen through the covers and away for another boundary. That was lovely from Khawaja. He timed his shimmy down the wicket nicely.
That was only the ninth boundary of the innings, in the 36th over.