Natalie Sciver is the new batter. Beaumont sweeps fine and picks up three.

Vic Marks
Ex-England spinner on BBC Test Match Special

"That was a superb piece of fielding. I'm sure Taylor thought she was going to get a single down to long-off but Van Niekerk anticipated brilliantly. It shouldn't affect the outcome but you never know..."

Dane van Niekerk returns, and is immediately swept for four by the supreme Taylor. That brings up 2,000 runs for her in T20 international cricket - only the second woman to do so, after her team-mate Charlotte Edwards.

Luus has a nice, loopy action, but it can go wrong - a full toss sits up juicily for Tammy Beaumont and she spanks it over the top for six.

England women's assistant coach Ian Salisbury on Sky Sports: "We want to play brave and positive cricket and we want to knock these off as quickly as possible."

Beaumont collects her first boundary with a slash through point. England are cruising here...

Vic Marks
Ex-England spinner on BBC Test Match Special

"The game is completely under control, the field is spread and you can just pick off those single. But I suppose this is Twenty20..."

Tammy Beaumont, hoping to make up for some horrible gaffes in the field, comes to the crease. Luus completes an excellent over - just four from it.

50 for Taylorpublished at 10.1 overs

10.1 overs

Eng 92-2

What a stunning knock from Sarah Taylor. She knocks a single down the ground to bring up a fifty from just 33 balls and she's barely played a shot in anger.

Chris Lawton: Absolutely love watching @Sarah_Taylor30, external bat, she seems to have so much time at the crease!

Derek Parry: @Sarah_Taylor30, external chancing her arm a little bit but a class act getting Eng ahead of the game.  

Daniels returns as Mignon du Preez aims to keep England guessing. Bit of a hairy moment for England as Knight saunters out of her crease and keeper Chetty misses with a throw that would have run her out comfortably. A poor full toss provides a good end to the over for England when Knight cracks a four through the covers, and at the halfway stage, the tourists are cruising.

Vic Marks
Ex-England spinner on BBC Test Match Special

"That was a full, straight ball, but she stood tall and it was a reverse tickle. She has played a few gorgeous shots - she's in prime form."

Ismail, who took a wicket in her first over and hasn't bowled since, is finally invited back to the party. Taylor brings up an excellent 50 partnership with a deliciously impudent reverse dabble for four.

Vic Marks
Ex-England spinner on BBC Test Match Special

"All is under control providing they don't lose wickets. They can be quite discreet about the way they pick up these runs now but I am not sure England like to play that way these days."

Dinesha Devnarain into the attack - just one wicket in 13 T20 matches for her. Is she really the right choice with South Africa desperately needing to break this partnership? Not with deliveries like that - rank full toss, splattered over the ropes for six by Knight.

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

"Jos Buttler plays that reverse-sweep - and another brilliant shot from Sarah Taylor. They watch it come right on to the bat."

Dane van Niekerk, who has impressed with the bat in the series, to bowl some slow, wristy leg-spin. Taylor plays a lovely improvised reverse paddle which runs away to the third man boundary. She had to time that perfectly as there was no pace on the ball. South Africa need wickets.

That's clever from Taylor - getting well outside her off stump to paddle Tryon behind square leg for four. And another! This time she lofts the bowler straight down the ground. Tryon recovers well with a delivery that just scoots past the outside edge on its way into the keeper's gloves. Then there are shouts of 'catch!' as Taylor plays an aerial cover drive, but it just eludes Luus at cover and runs away for the third boundary of the over. England on the charge.