Dean stars with four wickets; Wong takes three wickets on debut
Dunkley hits her first ODI century - off 87 balls
Lamb and Beaumont put on 127 for first wicket
England now lead multi-format series 6-2
Highlights on BBC iPlayer from 07:00 BST on Saturday
Nadine de Klerk returns... and that looks painful.
Sophia Dunkley has smashed the ball right back at De Klerk and the ball clips the end of her fingers on the way through.
Technically a caught and bowled chance, but a very, very tough one.
Sciver 61, Dunkley 72
England have scored 40 from the last three overs.
This is how Sophia Dunkley reached her half-century. The way she is batting three figures may not be far away.
Alex Hartley
Former England bowler on BBC Test Match Special
That is one of the most amazing sixes I've seen in the women's game! She's just gone and hit a six over backward point!
Wow, what a shot!
Sophia Dunkley has just played an uppercut with both feet off the ground and the ball has gone over backward point for another six.
Timing, technique, execution, brilliant.
Alex Hartley
Former England bowler on BBC Test Match Special
Image source, Getty ImagesIt's now time for England to accelerate and get as many runs as they can.
Henry Moeran
BBC Test Match Special
Just about had the legs to go over the boundary! That's six for Dunkley! A wonderful shot.
Now it is Sophia Dunkley's turn as she hammers Shabnim Ismail over long-on for six.
Next ball she plays a beautiful cut through point for four.
Nat Sciver ends the over with another pull into the leg side for four to move onto 61.
It doesn't matter where South Africa are bowling to Sciver, she is dispatching the ball for runs.
That's huge! Nat Sciver skips down the track and pummels Ayabonga Khaka over long-on for six!
It's 50 for Nat Sciver too! From just 39 deliveries.
Ayabonga Khaka serves up a full toss that Sciver was able to pull away for two.
There has been some fantastic shots by these two England batters, including this boundary by Nat Sciver.
That's delicious from Sophia Dunkley.
She spots the gap down at deep backward point and plays a lovely, wristy cut away for four.
Henry Moeran
BBC Test Match Special
Dunkley gets to 50 from 61 balls. She's played really nicely and put the foot on the accelerator.
Warm applause from the crowd and her team-mates as Sophia Dunkley nudges it into the onside for a single that brings up her fourth ODI half-century for England.
A brilliant innings.
The run rate is creeping up to six an over as these two batters continue to run hard between the wickets. As if it wasn't warm enough.
Sophia Dunkley is now up to 49 as the England balcony starts to fill up...
Another bowling change as South Africa search for answers.
Marizanne Kapp is back for her seventh over but England continue to manipulate the field, including a lovely square drive by Nat Sciver for two.
Sciver is now up to 42 and Sophia Dunkley is on 44. Who will reach 50 first?
Melissa Story
BBC Test Match Special
Sciver swept hard. Fantastic shot. Manipulating the field is what she does so well! The sweep shot is a massive strength of hers.
Brilliant technique from Nat Sciver as she again takes a big stride forward and sweeps through deep square leg for four.
South Africa bowling to Sciver's strengths here.
South Africa have no answers here.
Nadine de Klerk comes into the attack but her first delivery is short and Nat Sciver pulls away for four.
Melissa Story
BBC Test Match Special
It's been a game of good partnerships between these batters. They've adjusted to this format wonderfully.