Tash Farrant
England bowler on BBC Radio 5 Sports Extra

Laura Wolvaardt is much better against seam than she is against spin so this is why Heather Knight has brought Charlie Dean in a lot earlier than usual in the powerplay. It's a good battle going on but South Africa are fighting back.

Charlie Dean replaces Kate Cross and has got a breeze going across the ground to work with, that might help her to the right-hander.

Not quite on this occasion though, offering a full toss for Annerie Dercksen to whack through the covers for four.

Thumped down the ground for four!

Laura Wolvaardt ends Lauren FIler's fourth over in style. Has Filer got a fifth over in her?

Tash Farrant
England bowler on BBC Radio 5 Sports Extra

England look a more reliable, cohesive attack with Kate Cross there. She has learnt to adapt to the new ball and open the bowling for England.

Lauren Bell is struggling with her line recently having changed her technique last year, and she has been less consistent because of that. It is a good change.

A productive over for South Africa as the new ball starts to wear off and all of a sudden, the pitch looks a lot slower.

Annerie Dercksen starts to settle into her innings with two runs clipped through mid-wicket before driving through the covers for the same result.

Wolvaardt then slices a wider one past point for a much-needed boundary for her side.

Jack: This is why you go for Lauren Filer in your team, that pure pace and extra difference she adds is what the team needs. You have to accept that the odd delivery will go for runs, the same way you do with a leg spinner but the difference is worth it.

Wolvaardt drives through the covers for a couple more and then plays and misses at the final delivery, drawing gasps of disbelief from the slips.

Lauren Filer has bowled three overs and taken 2-12. She's been brilliant and in this kind of rhythm she'll want to keep going and going - but Heather Knight will have to manage her carefully.

Henry Moeran
Test Match Special commentator

At one end Kate Cross is bowling very accurate line and length, and at the other end we have this tear-away bowling from Lauren Filer which is thrilling to see. It's almost like two games of cricket going on.

Lauren Filer's two wicket-taking deliveries almost hit the exact same spot on middle stump.

Bullseye.

Laura Wolvaardt clips into the leg side for three but those are the only runs from the over as Kate Cross backs up the pressure beautifully.

Annerie Dercksen slams her bat down on a yorker as South Africa look to withstand a dominant opening spell from the England seamers.

Rufus Bullough
CricViz analyst

The wicket delivery from Lauren Filer which blew Tazmin Brits away was 118kph (73mph). In her six-year international career to date, she has never been dismissed by a quicker delivery than that.

Sune Luus was bowled by a 115kph delivery (71mph) but was also done by the swing. The ball swung 1.7° into her, then nipped away off the pitch 0.7°. No ball bowled by Filer today in her first two overs had more movement through the air.

A stunning opening burst from Lauren Filer. She can be wayward with her raw pace at times but this is a perfect demonstration of why she's so exciting with it.

The promising newcomer Annerie Dercksen is in at four and she won't face many tougher challenges than this in the early stages of her career.

Lydia Greenway
Former England batter on BBC Test Match Special

Suné Luus never looked comfortable against Filer and you can see why from that delivery. Her footwork wasn't as decisive as it should have been and the ball just tailed beautifully past her.

It's a joy to watch bowling like this!

Lydia Greenway
Former England batter on BBC Test Match Special

Fast bowlers can be expensive at times as the ball can fly off the bat, usually to the boundary. But it's often worth the risk when they get you early wickets with the gem deliveries in their armoury. England just need to manage their fast-bowlers' overs.

England's plan to Wolvaardt is also clear, as they refuse to give her any width to feed the glorious cover drive she possesses. It works pretty well for Kate Cross for the first four balls before she strays ever so slightly, and the South Africa skipper pounces for her first boundary.

They executed the same plan on Wednesday but Wolvaardt was chasing a low total so she could dig in. It'll be an interesting challenge for her when trying to set a first-innings score.

Rufus Bullough
CricViz analyst

A good toss to win this morning for England, with Kingsmead in Durban typically being a chasing ground. Only 15% of toss-winning captains choose to bat first, with two-thirds of matches won by the chasing side.

Lydia Greenway
Former England batter on BBC Test Match Special

This is why I am so pleased to see Lauren [Filer], she has that point of difference with her bowling. I don't think Tazmin Brits even saw that wicket ball coming towards her, she completely played the wrong line.

Hello!

Aggression from Filer, who has Sune Luus ducking out of the way of a fiery short ball as a lovely welcome to the middle.

Luus then gets quite lucky, getting a bit of glove on another short one and it trickles away for four. But South Africa's number three is definitely backing away from the pace so you can see England have come up with a deliberate plan here.