There's a right old party going on at Centurion now, the trumpeter leading a chorus of I Just Can't Get Enough. Was that Depeche Mode? Rabada to Root with drinks approaching. One of the South Africa subs has appeared with a full tray of biscuits, the sort you might see royalty serve up during afternoon tea. Root takes us there with a cover drive for four. 

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

"Cook is very mentally strong; he's got tenacity, concentration. It's very difficult to get him out of his comfort zone."

Piedt, a shadow to his right, skips in around the wicket and looks to turn the ball away from the left-handed Cook. Slip and short leg, Cook defending with the bat in front of his pad.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

"Alastair Cook has played really well. His footwork has been good and he's picked the length well. He looks in good touch. He'll be fancying a hundred."

As a batsman, how do you put that uneven bounce out of your head? How does Alastair Cook stop himself from worrying about the one that might hit him on the ankle? Then again, does Cook think about anything when he's batting? Probably just his hunger for runs. Like Pacman eating the dots.

Dane Piedt to Alastair Cook. Piedt might have a lot of work to do while the seamers rotate. In the crowd, the South Africa fans have found their voice. From behind the stumps, De Kock tells the Proteas "let's go". One more tonight and they will be all over this match.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

"There's no point in reviewing that."

Image source, Getty Images

Looking again, it wasn't quite a mullygrubber, but it was very definitely a guzzunder. (Goes under, geddit?) In fact, the Jam could write a song about that delivery Going Underground. Joe Root is the new man, immediately seeing one go under his bat too. Fortunately for him, it's outside off stump. This pitch, placid so far, has awoken from its sleep. The mountain called Monkey has spoken.

Michael Vaughan
Ex-England captain on BBC Test Match Special

"There's nothing you can do about that. That's just rolled along the deck. He's gone back to a ball he should have gone back to; it should have bounced about thigh-pad height. You just hope your name's not on a ball like that. And this is only day two..."

Craig Gray: Drop Hales, bring Buttler back as keeper and just move everyone up a place.

James Green: Hales has been in a series winning England team away to South Africa. Opening batsmen need time. I'd give him the summer at least.

Dane Piedt and Nick Comtpon are playing the same ball on repeat here. Just back of a length, touch of turn, Compton shuffling across to defend from the crease. He's a man who bats in spurts, Compton. When someone puts 50p in his meter, he can get a spurt on. When he slips into defensive mode, he could put Tigger to sleep.

Richard Ryan: Test cricket has moved on, but the basics of an opener is vital in a five day match. Simples!!

Alex Franks: Time to give Burns or Bell-Drumond or Vince a try.

Ash Sales: Bring back Bell and have him open. We know he's good enough.

The wholehearted Kagiso Rabada returns, erring on to the hips of Cook to be clipped for four. That's so difficult to do, but Cook makes it look as challenging as blowing the head from a dandelion. Speaking of dandelion, you don't see dandelion and burdock about much any more, do you? And what was is dandelion and burdock?

HarryT2k: Perfect Saturday viewing - the great South African Cook-off!!

Spin, with Compton almost turning Dane Piedt into Temba Baat short leg. It's a near-impossible chance, but we've seen someone of those taken in this series. Touch of turn for Piedt, with Compton pretty much exclusively working on the leg side. Another maiden.

All a little flat in Centurion at the moment. If this was Edgbaston or Headingley on the Saturday evening of a Test match, the well-oiled would be causing a right rumpus. Probably involving a beer snake, a beach ball and a man dressed as the Queen. Alastair Cook is one of the reasons for the subdued home crowd. He's like a Dementor, sucking the life out of bowlers and all who support them. Another Abbott maiden.

Michael Vaughan
Ex-England captain on BBC Test Match Special

"Compton is settling in. He's done the hard yards here - he's given himself a chance and England are setting the foundation."