De Kock & Amla put on 239 for 1st wicket
Quinton de Kock made 135 from 117 balls
Captain Hashim Amla hits 22nd ODI 100
Root made superb 125 for England
England lead five-match series 2-1
Ben Stokes replaces fellow left-hander (and fellow redhead) Morgan, and looks on as Root steers a two to long-off. Despite those doom-laden predictions of rain earlier, it's still looking set fair for now. Root isn't dawdling, a single takes him to an even 87 from 87 balls and brings Stokes on strike for the first time. He has a look for his first couple of deliveries.
Vic Marks
Ex-England spinner on BBC Test Match Special
"He barely timed a ball. It was just one of those days when just couldn’t get it."
Geoffrey Boycott
Ex-England batsman on BBC Test Match Special
"I don’t think that was a very good innings. I don’t think he assessed the pitch. He tried hard thrashing at the ball immediately when he came to the crease.
"I don’t think he assessed that that wasn’t the best way forward. I am sure it is getting harder to play the big shots as the ball gets softer.
"If he sits in the dressing room and contemplates he will look to play a different type of innings."
Morgan c Amla b Wiese 8 (Eng 187-4)
Image source, Getty ImagesAnd Wiese gets his reward as one of the more unconvincing innings of Morgan's 158-game ODI career is ended as another mistimed stroke gives Amla an easy catch at mid-wicket.
Wiese has bowled tidily today, certainly serving up fewer free pies than the Behardien/Duminy fifth-bowler combination did in Bloemfontein and PE. Root adds a single, Morgan steers a two to long-on.
Geoffrey Boycott
Ex-England batsman on BBC Test Match Special
"They mustn't get complacent. The game can change quite quickly."
Abbott to continue - which means that SA's four seamers will all have bowled seven overs by the end of this over, with spinner Tahir having sent down five. Root is still chugging along nicely, but Morgan misses with another pull shot - his six runs have come from a rather laboured 21 deliveries.
17 overs to go, we've been playing nearly two-and-a-half hours already, is ABDV looking at an over-rate fine here? It'll be a shortened interval whatever happens.
Image source, Getty ImagesGeoffrey Boycott
Ex-England batsman on BBC Test Match Special
"It will be interesting when we get to Ben Stokes and Moeen Ali, who are hitters of the ball. It hasn't been difficult but not easy. I said last match, when Stokes came in to strike it, it wasn’t easy and it could finish up the same here."
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Keir McCumiskey: Morgan playing like he's left his pancakes in the frying pan and the job on full heat. Slow down man!
He's certainly not going to "batter" South Africa the way he's been playing so far...
Eng 181-3
More drinks have been earned by the players. South Africa are in a huddle - can they put the brakes on England from here?
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Tom Fisk: Imagine how good Joe Root is going to be when he's a fully grown adult! #babyface, external
ABDV shuffles his bowlers as Wiese returns - and Root shows his captain how you go about coming down the track to seamers, clattering his second six of the day over long-on where it hits a plastic chair just over the boundary.
Tahir's off after one over as the Proteas turn back to opening bowler Kyle Abbott - but once more, Morgan isn't quite timing the ball as well as we know he can, coming down the track to the pace bowler but not connecting. Root gets one in the ribs but helps it through mid-wicket for two, and a single takes him to 73.
Image source, Getty ImagesGeoffrey Boycott
Ex-England batsman on BBC Test Match Special
"It is a good pitch, just pick your ball. You don’t have to play big four-ball shots every ball.
"It looks frenetic, fraught this innings."
England: 168-3 from 30 overs (won toss)
Batsmen: Root 70, Morgan 3
Fall of wickets: 36-1 (Roy 20), 161-2 (Hales 65), 162-3 (Buttler 0)
Bowling figures: Abbott 5-0-25-0, Rabada 7-0-35-2, Morkel 7-0-35-0, Wiese 6-0-37-0, Tahir 5-0-31-0
Root moves to 70 from exactly 70 balls as he turns Morkel to leg for a single, Morgan comes down the pitch and has a swing but he's beaten outside off stump - he's not long been in but is batting like a man in a hurry.
Simon Hughes said before play that 280-300 would be a good score here. If you're a follower of the "double-the-score-after-30-overs" maxim, 300 should be well within England's range - and I'd say 320-330 could well be a winning score on this pitch. (Famous last words?)
Morgan reverse-sweeps and misses, and is struck squarely in the chest. Even at Tahir's pace, that's got to hurt. Good over for SA.
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Stuart Mitchell: So pleasing to have an ODI side that are playing with right attitude and confidence. All of a sudden looks a possible 400 pitch!
David Whittam: Good solid scoring from England. Time to put the foot on the gas now though.
Mat Harris: People moaning about scoring slowly. Looks like 300 is going to be par, we are on course for that.
As often happens, South Africa recall Imran Tahir immediately after a wicket falls - and Morgan goes after him straight away, slog-sweeping him where it reaches the mid-wicket sweeper on the first bounce. Root takes a single to fine leg - but having learned from the Jason Roy run-out, does not take a second run with the ball already in the fielder's hands.