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Wolvaardt 55; Ecclestone 2-27, Glenn & Sciver 1-18
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Laura Wolvaardt is looking to give herself as much space as possible by coming out of her crease and moving outside leg stump but Sophie Ecclestone is very canny.
She throws it wider and follows her and Wolvaardt is twice only away to drive away for a single.
The current scoring rate gets South Africa to 106. You wouldn't think that is going to be enough against this England side.
Alex Hartley
Former England bowler on BBC Test Match Special
They are but I've been quite impressed with Tucker, she's looked to play her shots.
Emily Windsor
Southern Vipers batter on BBC Test Match Special
South Africa are in a lot of trouble here.
Nat Sciver is going through the variations here.
She bangs the ball in short and Delmi Tucker almost picks out Katherine Brunt at mid-on. She decides against going for the catch and there's a shout from Amy Jones to go for the run out by Brunt's throw misses.
A bouncer is well stopped by Jones as Tucker looks to ramp away, before a slower ball is just patted into the covers.
Alex Hartley
Former England bowler on BBC Test Match Special
It is good to see that Issy Wong can run in and be fearless.
Heather Knight is rotating her bowlers a lot in this innings. I suppose with six solid options you've got that luxury.
Issy Wong concedes just two singles and a leg bye from her third over.
She's only gone for nine so far and has bowled 13 dot balls.
Here's how Sarah Glenn picked up her first international wicket of the summer...
It wasn't the best shot choice from Anneke Bosch.
Georgia Elwiss
England all-rounder on BBC Test Match Special
It is good running and it's something that South Africa need to be really good at through this middle phase. They're struggling to find the boundary and are losing wickets, one thing they can control in their running between the wickets.
Debutant Delmi Tucker is the new batter. Not nice coming in at 69-5 and facing the number one bowler in the world.
She gets off the mark straight away with a couple, before Laura Wolvaardt gets a strike of luck as an inside edge goes through her legs, rather than into the stumps.
South Africa need her to bat through.
Georgia Elwiss
England all-rounder on BBC Test Match Special
It's clever bowling from Sophie Ecclestone. She's so used to people trying to get after her. It's quite a poor shot, across the line from Tryon.
Emily Windsor
Southern Vipers batter on BBC Test Match Special
Three reds and Chloe Tryon has to walk about to the dressing room.
Tryon lbw b Ecclestone 9 (SA 69-5)
Crashing into leg stump!
Chloe Tryon was looking to come down the wicket and then tried to sweep Sophie Ecclestone.
The pace and skiddy nature of Ecclestone catches Tryon out and South Africa are in a whole heap of trouble.
Georgia Elwiss
England all-rounder on BBC Test Match Special
It is last chance saloon for South Africa, they need this to be not out.
There's no bat.
This looks very good.
Emily Windsor
Southern Vipers batter on BBC Test Match Special
Chloe Tryon has tried to sweep and heave it leg-side. Ecclestone was convinced.
Sophie Ecclestone strikes with her first ball back!
She's got Chloe Tryon out lbw.
Tryon, after a chat with Laura Wolvaardt, reluctantly reviews. She thinks she's a goner.
Georgia Elwiss
England all-rounder on BBC Test Match Special
Lovely shot by Tryon, using her feet. That long-off boundary is one that she can target with the strength she has.
Chloe Tryon batted really nicely in the third ODI on Monday and she's started nicely here too.
She takes a step down the pitch and that allows her to get to the pitch of the ball and take Bryony Smith downtown for a one-bounce four.
The bad news for South Africa? We've only seen one over of Sophie Ecclestone so far. She's going to be hard to score off. She's coming back on now.
Georgia Elwiss
England all-rounder on BBC Test Match Special
Well, she's had a rest, hasn't she!?
Daniel Norcross
BBC Test Match Special
At 37 years of age, Katherine Brunt is going long-on to long-on at the moment.