50 for Joe Rootpublished at 22.5 overs
Eng 129-1
Now it's Root's turn to salute the dressing-room after another dabbed single, this time into the covers.
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
Mark Mitchener
Eng 129-1
Now it's Root's turn to salute the dressing-room after another dabbed single, this time into the covers.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
"He is in really good form. What is interesting is how consistent he has become."
Eng 126-1
Rabada returns in place of the expensive Tahir, and Hales is the first of the two England batsmen to reach the landmark, dabbing a single off his hip for his fifth ODI fifty from 60 balls.
Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special
"He didn’t get his body in that athletic position to really hold onto it."
Eng 125-1 (Hales 49, Root 48)
Half a chance? Root chases one outside off stump, the ball goes low to keeper Quinton de Kock's right and he can't lay a hand on it as the ball bounces under his outstretched mitt. It's away for four - both batsmen are close to raising their bats for a half-century.
Vic Marks
Ex-England spinner on BBC Test Match Special
"A skimmer and it just kept going through the thin air. He will like that one, Joe."
Where did that come from? Root leans back and hits a low, skimming six over cow corner!
England are still milking Tahir for ones and twos - but with Buttler still in the hutch, there's plenty of firepower to come in this England XI. Hales finally connects with only his fifth boundary of the day, squeezing a four between mid-off and extra cover - and when SA move the field to put in a deep cover, Hales effortlessly sweeps another four to where the fielder had just been removed!
Vic Marks
Ex-England spinner on BBC Test Match Special
"It feels like old Joe but I don’t think he is 25 yet. He is the rock in the middle order."
England: 99-1 from 20 overs (won toss)
Batsmen: Hales 35, Root 36
Fall of wickets: 36-1 (Roy 20)
Bowling figures: Abbott 5-0-25-0, Rabada 4-0-18-0, Morkel 4-0-17-0, Wiese 4-0-19-0, Tahir 3-0-15-0
Simon Hughes
BBC Test Match Special
"Fantastic shot. Brilliant shot. Just fractionally short and pummeled to deep square leg."
Hales has a big heave-ho against Wiese, but only connects with fresh air. Had he connected, it would have sailed out of the ground and at this altitude probably up, up and away to bother any passing wildebeest. Root shows him how it's done with a well-timed pull shot past the square leg umpire. He's overtaken Hales.
#bbccricket
Stephen Miller: Of course one-day form should count for Test selection (see 12th over) - if you're a Test cricketer, which Alex Hales isn't.
Luke Marshall: Tests & limited overs cricket require different skill sets. But then again, there's David Warner.
Charles Tilley: If not Hales to open in Tests then who? This opener merry-go-round to quote Boycott, is absolutely rubbish!
Root tucks into a shorter delivery from Tahir but is struggling to beat the infield which includes livewire fielders Du Plessis and De Villiers. But after three dot balls, he manages to break the shackles, slog-sweeping the leg-spinner for four. Tahir has 0-15 from three.
#bbccricket
Kieron Bird: When England bat, I live in fear of my phone beeping incase it's a wicket alert. When England bowl, it's the most exciting sound.
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Simon Hughes
BBC Test Match Special
"A hint of this guy’s action reminds me of Alan Donald, obviously not as quick."
"I know who I would rather face," Vic Marks replies.
The tall Wiese resumes proceedings, and England's steady progress continues as Hales and Root's second-wicket stand reaches 50 from 74 balls. Root has contributed 26 to the partnership, Hales adding 23.
Vic Marks
Ex-England spinner on BBC Test Match Special
"It is a good contest. England haven’t lost a wicket to a bowler just a careless run out. South Africa have been good in the field, they look sharp.
"England have been good but quite cagey. They are playing another way today, it hasn’t been crash, bang, wallop."
While the players take drinks, some news from Ireland's latest T20 international in Australia.
They lost by 11 runs to Papua New Guinea in Townsville, Queensland, but finished as 2-1 winners in the series.
Sese Bau (25) and Charles Amini (24) helped Papua New Guinea post 116-8 while Tim Murtagh picked up three wickets.
Niall O'Brien top-scored with 27 but Ireland slipped from 49-2 to 105 all out on a sluggish pitch.