After a disappointing series opener, when they were bowled out for 186 in Kimberley, England were in need of a response and their bowlers delivered in ruthless fashion.
But before Dean and Ecclestone got to work it was Filer who was electric, making the most of the new ball with a hostile opening four-over spell that set the tone after captain Heather Knight won the toss.
Opener Tazmin Brits drove her first ball for four but Filer immediately corrected herself, firing the ball straighter and knocking middle stump out of the ground before she gave number three Sune Luus a tough short-ball examination.
Luus was forced to duck underneath her first ball as Filer greeted her to the middle with a bouncer and continued to force her back into her crease, eventually nailing her plan to perfection as a fuller delivery beat the batter for pace and the stumps were splattered once again.
From there, captain Wolvaardt and the emerging talent of Dercksen regrouped and blunted England’s attack effectively, calmly rotating the strike and pouncing on any width to accumulate a steady fifty partnership.
But chaos followed as Dean – with a huge helping hand from South Africa’s atrocious shot-selection – turned the game on its head.
While no single player is ever to blame for a collapse, Dercksen’s soft dismissal kickstarted it and she was dealt a harsh lesson in taking responsibility once you are in as a batter.
The all-rounder chipped an innocuous delivery from Dean to point after a lapse in concentration following the drinks break, before Kapp’s bizarre shot rocked the line-up of which she is so often the saviour in tricky situations.
Wolvaardt, playing her 100th ODI, made a costly error in judgement by trying to play Ecclestone off the back foot having previously been so disciplined – and from there the Proteas unravelled with their two superstars gone in the space of four balls.
Filer returned after Tryon added a quick stand of 26 with Nonkululeko Mlaba, bowling the latter with a fierce yorker and finishing with 3-32 – including an average pace of just under 74mph, the fastest spell of her ODI career to date.
England must now protect their precious commodity with the Ashes looming in the new year.
