Rabada still has two slips in, but Hales is happy to plunder singles to third man from anything served up wide - and they're still peppering Root with the odd bumper, before Root pushes a fuller delivery to mid-wicket for one.

Theo Bowyer: Criminal from Roy... A dive would have saved him!

Mou 84: Sand needs to be brushed up from that Centurion wicket. Roy's bat got stuck in the ground.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

"It has been the same sort of bowling from South Africa, good balls but some sloppy short balls. 20, 30 runs can make the difference."

The gentle giant Morne Morkel, newly crowned demon fielder of the Highveld, is into the attack in place of Abbott. Hales is moving up through the gears with a two and a single - Root's first ball from Morkel is also a bouncer, as though it's a tactic they have planned for the young Yorkshire tyke. But he fends it off for a single, and Hales nicks the strike by dabbing one to third man. Stand by your beds, Boycott's coming on TMS...

Image source, Getty Images

Simon Hughes
BBC Test Match Special

"That really is a gimme wicket."

Replays show Roy was only really jogging that first run. And it appeared to be a late call for the second.

Joe Root in at first drop for England. His first ball is a bouncer, which he evades.

Simon Hughes
BBC Test Match Special

"Perhaps he should have dived. That was a poorly judged run because the bowler was in the way. Roy assumed because it was Morkel he would struggle to get it back. He didn't even run the first run quickly - but he'll learn from that."

Rabada was impressive in the Test series, but his line and length hasn't been quite what his captain would have wanted today, as Roy tucks into a shorter delivery and pulls it for four. Probably one of the Surrey right-hander's favourite shots. Roy then pushes the ball to third man, comes back for a second run and has to take a rather roundabout route, having to run round the bowler. South Africa appeal for a run-out, third ump having a look...

Simon Hughes
BBC Test Match Special

"A very positive, smooth start for England, so far. Maybe they don’t set targets anymore, just get out there and bat."

Hales guides Abbott for four just past second slip - cynics might suggest that it was the sort of shot which would have seen him caught at third slip in a Test... I wonder if he'll be walking out with Captain Cook when the Sri Lanka Test series begins in May? His Test struggles aside, there's no doubt about his ability in limited-overs cricket as Hales squeezes his second boundary of the over past backward point.

Image source, PA

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

On her scary, storm-hit flight from Port Elizabeth: "I genuinely thought it was the moment. I said, 'I love you Mum' or something."

There are still plenty of empty seats at Centurion as Roy continues to dominate the scoring, a controlled pull shot off Rabada bringing him four past the diving man at long leg. An exchange of singles means Hales is finally off the mark, though to be fair to the Notts man he's only faced five of the 24 legitimate deliveries sent down today.

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

"It is going to be an interesting wicket to bat on. 

"Sometimes you are not sure if it will fly through or keep low. Both batsmen will be wary of it."

Still some variable bounce from Abbott, but Roy takes a couple of steps down the track and lifts him over mid-on for four. SA respond by bringing fine leg up, allowing them to put another fielder back. A single takes Roy into double figures

Jon Dunn: England go with five specialist batsmen, two all-rounders, three bowlers & uniquely, one specialist fielder.

Thomas Measures: Other teams around the world must be so envious of England, not only have one world class all-rounder, but two in Mo and Stokes.

Amos Kemp: Really don't mind Broad not being picked. He's far more destructive in red-ball cricket. He's only there if someone gets injured. 

Roy adds a leg bye to the score, bringing Alex Hales on strike for the first time. And Rabada also finds some lift, pinging in a bouncer which beats both batsman and wicketkeeper, and disappears for four byes. Extras top scoring so far.

Vic's not wrong about those thunderstorms, by the way. AB de Villiers, Quinton de Kock and TMS's Ebony Rainford-Brent were all aboard a plane which had a bit of a scary landing in a storm the other day, while the first women's ODI on Sunday was interrupted by rain, thunderbolts and lightning (very, very frightening). But it's blue skies and fluffy clouds for now.

Image source, Getty Images

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

"That is quite a brave shot but he committed to it and played it on the top of the bounce."

Kagiso Rabada takes the second over - and as if he's spent the first over getting his eye in, Roy immediately takes the attack to Rabada with a well-timed extra-cover drive for four.

Vic Marks
Ex-England spinner on BBC Test Match Special

"I don’t think I have ever attended a match in Centurion that hasn’t been affected by weather at some point.

"Thunderstorms roll in, you don’t get much drizzle here, hopefully they will go out of the way today."