England comfortably chase 112 with 30 balls to spare in six-wicket win
Dunkley hits 59 - her maiden T20 international fifty
Hosts take unassailable 10-2 lead in multi-format series with two T20s to play
Brunt takes career best 4-15 as Proteas restricted to 111-9
Seamer moves to 102 T20i wickets, equalling England record
Wolvaardt 55; Ecclestone 2-27, Glenn & Sciver 1-18
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Target 112
Well bowled, Ayabonga Khaka. She ends her four overs with figures of 3-13, the seamer has helped keep this respectable for South Africa.
She's varied her pace well and made England's life that much trickier than it could have been.
Alex Hartley
Former England bowler on BBC Test Match Special
Khaka is coming back into the attack. I think she should have bowled the over before to be honest.
Target 112
It was a very good over from Tucker, only one from the first five balls before Knight brings out the reverse-sweep.
It's hit well again, taking the ball up and over the fielder at backward point, four runs and England need 20 more to win.
Alex Hartley
Former England bowler on BBC Test Match Special
Dunkley has guided it to the fielder. Had she really hit it it would have gone into the stands.
She has done her job.
Dunkley c Khaka b Bosch 59 (Eng 87-4)
The end of a fabulous innings from Sophia Dunkley.
The previous ball had been nailed for a big, big six over long-on and she was after another maximum.
It was a full toss from Anneke Bosch, Dunkley tried to hit it over long leg but got a top-edge and Khaka takes a good catch on the rope.
Target 112
Struck sweetly but Heather Knight. A firm pull shot and the placement is perfect, splitting the two fielders in the deep to earn her a boundary.
Ayabonga Khaka has been the real plus point for South Africa tonight. The seamer has three wickets now, all bowled, and started by dismissing Danni Wyatt...
Alex Hartley
Former England bowler on BBC Test Match Special
Dunkley is trying to hit the ball too hard in the last couple of overs. If she swings easy she will time it a bit better.
A very tidy over from Delmi Tucker. The off-spinner concedes just four singles from it.
Heather Knight has joined Dunkley. Halfway through the chase and it is time forthe players to take drinks.
While Sophia Dunkley is still there, England won't have any worries.
Promoted up to open and she has been superb, hitting powerfully down the ground and through mid-wicket.
Dunkley 50, Knight 1
South Africa are showing some fight here, just to put a little bit of doubt in England minds.
The home side should this get over the line comfortably but another quick wicket and it might get nervy.
Alex Hartley
Former England bowler on BBC Test Match Special
Brilliant delivery from Khaka. You would still say it is England's game.
That is Sciver's first failure in a long time.
Sciver b Khaka 13 (Eng 69-3)
Bowled her! It's three for Khaka!
The seamer gets the big wicket of Nat Sciver, who was down the pitch and trying to work the ball to leg but is deceived in the flight.
It was a leg-cutter and it just snuck through Sciver's defence to hit middle and leg.
Alex Hartley
Former England bowler on BBC Test Match Special
Dunkley is doing exactly what she was asked at the top of the order - score at a good run-rate. She is proving she is good enough.
Eng 69-2
A single worked out to long-on and Sophia Dunkley has a half-century. A superb start from her in her new role at the top of the order.
Target 112
A quieter over but England are cruising. South Africa already seemed disheartened and drops like that from one of their top fielders is not going to help.
Alex Hartley
Former England bowler on BBC Test Match Special
Ismail is one of South Africa's best fielders. She should have taken that.
Eng 65-2
Oh dear. That just about sums it up for South Africa.
A gentle chip down the ground from Dunkley off Tryon and Ismail comes around from long-on, gets both hands to it but shells the catch.
Dunkley is only able to take a single from a free hit after Ismail overstepped for the second time in the match.
No bother, though, Sciver brilliantly thumps the next ball away for four, just in front of square.
It's just a matter of time now for England.
Dunkley's first six of the night wasn't too bad either...