I like to think they're reminiscing about their days of being on the same side at Yorkshire. Probably not, mind.

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The worst moment of yesterday was when Joe Root was struck by a vicious bouncer from Mitchell Starc.

Root didn't get into position quickly enough and was struck flush on the grille by Starc, sending a bit of his helmet spiralling to the ground.

Starc and the Australian players rallied around Root - showing that pre-series words are just that: words - before he was checked out by a doctor.

He had a routine concussion check with the doctor and England say he's fine to bat. In fact, he was last seen heading to the nets.

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Here's how our momentum-o-meter currently looks...

Image source, BBC Sport

Among England's many concerns yesterday was James Anderson, who was looking even grouchier than usual.

Anderson dismissed Tim Paine with a gorgeous new ball delivery but then didn't bowl after lunch, and spent much of the afternoon grimacing at fine leg.

He took a tablet on the pitch and the word from the ground today is that he has bruising on his shoulder after being struck when batting, but it shouldn’t affect his bowling.

"I don't know where this mystery injury has come from," Stuart Broad told Test Match Special yesterday.

"He's not moaned about anything, said he was sore or injured. It's hard work, we had to rotate bowlers."

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Steve Smith's ton, killer moths and Tuffers overcomes an ibis.

What else would it be but the Pint-sized Ashes? Have a watch below.

"It was not just the runs that Smith scored that had such an effect, but the way he ground England down in the afternoon heat.

"Since the final Ashes Test in 2013, Smith has made 21 centuries. No-one in the England team has made more than Root's 11."

Not my words, but those of Stephan Shemlit, who has been watching on from the press box in Brisbane. Read his report from yesterday to get yourself up to speed.

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Hiya! Welcome to day four at the Gabba. I've completely lost track of time and days. All I know is that I watched Steve Smith make a century, I went home and dreamed about Steve Smith making a century. He's haunting me.

We'll be bringing you the usual over-by-over commentary, along with any nonsense that we stumble across, and Test Match Special will also be keeping us company. Settle down for the night, folks. This finely poised Test could go either way.

A sparkling century by Steve Smith, a tactical let-up by England and a dreadful hook shot from Alastair Cook.

They were the three defining factors of yesterday's game, and it feels like they could come to define this match.

England have a lead of seven. Australia have their tails up. It might not be pretty, but it will be engrossing.

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