Here goes. Let's talk about James Vince...

Graeme Edgar: I hope England stick with Stoneman. He has shown the capacity for Test matches without weight of runs, and his bouncer issue can be worked on. Alternatively we keep playing opener roulette.

John Campbell: Cricketers need Test experience to come good. Daft if England keep dropping the likes of Vince and Stoneman after five Tests. Instead, continue with them, invest in them, give them time, coach and encourage them to grow into the long form of the game.

Stoneman was jumping as he was struck on the pads by Starc to be removed for a duck.

It's been an odd series for the opener, who has looked assured at times but barely capable of making a run at others.

But is there anyone out there who could come in and do better?

Michael Vaughan
Ex-England captain on BBC Test Match Special

I am concerned about Stoneman. If you look at his run of scores since he got hit on the head in Perth, he's hardly got a run. He's not been getting his head back towards the ball. I watch him practice quite a bit and I don't see him practise enough against the short ball. I see him practise how a county player practises.

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Alan Taylor: Out batted, out bowled, out fielded, out thought and out fought.

Earlier, Australia wore England down on a scorching day at the SCG, where the temperature reached a frankly ridiculous 57.6C.

Shaun Marsh, starting on 98, duly completed his second ton of the series, making 156 before he was run out. He celebrated his century with younger brother Mitchell, who then did vice-versa as he also made his second ton of this Ashes. Tom Curran bowled him next ball but the damage was done for the tourists.

The Marsh brothers put on 169, with contributions from Tim Paine, Mitch Starc and Pat Cummins carrying Australia to declare on 649-7, a lead of 303.

Michael Vaughan
Ex-England captain on BBC Test Match Special

When England lost those two wickets - particularly when Cook went - I thought this could all be over today. Root is showing a lot of courage and determination and sending a message to his team, "We might be losing, but we don't give in."

Hello to those of you just waking up. And yes, it's not looking too clever for England.

They close day four on 93-4, still trailing Australia by 210 runs. They face an almighty task to bat all day tomorrow to save the Test and avoid a 4-0 series defeat.

Captain Joe Root has batted serenely to end unbeaten on 42, with Jonny Bairstow batting responsibly to end 17 not out.

The wickets to fall? Mark Stoneman went for a duck, snared lbw by Mitch Starc and failing with his review. Alastair Cook was then bowled by a Nathan Lyon ripper.

James Vince did a James Vince. Yet again he looked good but then edged off driving to first slip for 18. Dawid Malan was caught lbw by a Lyon delivery that skipped on.

Earlier, Australia converted their overnight 479-4 into a mammoth 649-7 thanks to Shaun Marsh's 156 and brother Mitchell's 101.

Simon Mann
BBC Test Match Special commentator

Root and Bairstow have just given England just a fraction of hope.

Slip, leg-slip, silly point and short leg all in for Lyon as he wheels in to Root.

The England captain goes back and across to get his pads outside the line of off-stump and defends the first three.

The fourth slides towards leg and Root taps it straight down, before playing a forward defence to the fifth.

Here's the last ball of the day...and Root drives it firmly square, with Khawaja blocking it at silly point.

Rosy. Not long left for the fans and players to swelter now - this should be the final over of the day. Nathan Lyon to bowl it...

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Cummins drops short and Root plays a well-timed glance into leg for an easy single.

Bairstow leaves or fends away the next five balls.

Responsible stuff from this pair, who of course both fell around this time on day one to derail England's first innings.

Tahir: Make no mistake, this an absolute destruction in the Ashes. Humiliating performance. How any of the top order keep their place is beyond me. Root continuing as captain should be seriously questioned.

Bairstow smothers a few and pads up to the rest. A sedate maiden for Lyon.

There should be eight overs remaining but we won't get them in today.

A brief pause as a helmet is brought out for Usman Khawaja to come in to silly point. Plenty of men around the bat to try and up the pressure on this pair.

Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special

I think Ballance is going to have the worst tour of all - he's been here for a 4-0 loss and I don't think he'll be taken to New Zealand. It's tough on him.

Joe Root stands tall to elegantly punch off the back foot through the covers for two.

It's been a long tour, but you don't begrudge the England captain making sure it goes to the final day with this kind of knock.

Cummins brings out the bouncer and Root easily ducks under it before leaving the next outside off. He works the last to Nathan Lyon at backward point - the off-spinner holds onto the ball and will be coming on next.

Thanks Amy, lovely stuff.

Hazlewood is going to have a rest - here's Cummins back into the fray...

Steve Smith serves up something full and loopy and Jonny Bairstow's eyes light up, but he cracks it straight towards a fielder. He gets hold of that one though, dragged down by Smith, and Bairstow swings and hoicks it for four.

And that's me done for the day. Jack Skelton will take you through to the close.