Eng 16-2published at 6 overs
Trail by 287
Root works off his pads for one to get off the mark.
Lyon ends the over to rapturous applause. You sense it won't be the only ovation he gets today.
Root 42*, Bairstow 17*
Two wickets for Lyon
Aus 649-7 dec - lead of 303
S Marsh 156, M Marsh 101
Moeen 2-170, Crane 1-193
Australia lead five-Test series 3-0
Day five starts at 23:30 GMT
Jack Skelton and Amy Lofthouse
Trail by 287
Root works off his pads for one to get off the mark.
Lyon ends the over to rapturous applause. You sense it won't be the only ovation he gets today.
So you know how all of you were asking about the last time all five Tests in an Ashes series went all five days...
Here comes Joe Root. Captain's knock required.
Dan Norcross
BBC Test Match Special
There's not a lot Alastair Cook did wrong there.
Vic Marks
Ex-England spinner on BBC Test Match Special
That is a great delivery.
Cook b Lyon 10 (Eng 15-2)
A tremendous delivery from Nathan Lyon does for Alastair Cook, pitching on middle, turning and hitting the top of off stump.
The shot wasn't too clever though - Cook going back and then desperately trying to angle the bat at it too late.
Not to take anything away from the ball - Lyon is finding serious bite at the SCG. A classic off-spinner's dismissal to the left-hander.
Oh my days. Lyon absolutely rips one past Cook's outside edge first up.
An absolute jaffa. Better than anything England's spinners offered up. Australia look positively gleeful.
A more sedate over after that early drama, Cook punching down the ground nicely for a couple, then nudging into the covers to move into double figures.
Nathan Lyon is going to enter the fray. Will he show up England's spinners?
Dan Norcross
BBC Test Match Special
Suddenly batting looks very difficult.
Trail by 293
Cook managed to sneak through for a single after that drop.
That brings James Vince on strike. The Hampshire man gets off the mark by flicking fine for four.
Dan Norcross
BBC Test Match Special
Hazlewood has his head in his hands.
Glenn McGrath
Ex-Australia pace bowler on BBC Test Match Special
That's a regulation catch! He's quite wide at first slip. I haven't seen Shaun Marsh in the slips too much.
Lifeline for Alastair Cook.
Josh Hazlewood sends one down the middle of the corridor of uncertainty, Cook pushes at it and nicks it, but Shaun Marsh shells it at first slip.
He was standing very wide of the keeper and ended up having to chuck his hands to his right to try and get it.
Tremendous bowling from Hazlewood but poor positioning from the Aussie cordon. Should Tim Paine perhaps be diving for it if the slip is that wide? Why was Marsh that wide in the first place?
Ed Smith
Ex-England batsman on BBC Test Match Special
It's a forlorn trudge off for Mark Stoneman.
Stoneman lbw Starc 0 (Eng 5-1)
Ball tracking duly shows that would have clattered into the top of leg stump.
Stoneman thought it might have been going down but it certainly wasn't and England lose a review.
A straight, quick one from Starc that Stoneman played around.
Ed Smith
Ex-England batsman on BBC Test Match Special
My feeling was it might have been a bit high.
Mitch Starc gets one through and onto Mark Stoneman's pads. Huge appeal - given!
After consultation with Cook, Stoneman reviews.
This looks out.
Andrew Samson
BBC Test Match Special statistician
Alastair Cook is the sixth Test player to get to 12,000 runs. He's also the youngest at 33 and 13 days.
Ed Smith
Ex-England batsman on BBC Test Match Special
An extraordinary achievement by a remarkable man.
Cook chips it into the leg side and totters through for one.
And that's 12,000 Test runs for Alastair Cook. What a tremendous player.
He needs another 401 runs to overtake Kumar Sangakkara in fifth in the all-time rankings.