Wiegman has faced questions over her team selection in recent weeks with Williamson at the centre, given the impressive form of Manchester City's Alex Greenwood – an obvious replacement.
Greenwood was brought into the side to play alongside Williamson but it did little to improve England's defensive performance as individual errors were consistent and almost costly.
Stanway's slow response to Williamson's pass did not help, and the Bayern Munich midfielder had earlier been involved in a mix-up with Esme Morgan that gifted Hildah Magaia an opportunity she could not take in the first half.
Wiegman made numerous changes throughout the second half, bringing on experienced defenders Lucy Bronze and Millie Bright but South Africa continued to cause concern.
Bronze was caught out with a ball over the top but was fortunate Kgatlana was offside, just before Bronze had to intervene to block another goalbound strike by the South Africa forward.
England’s defensive performance against Germany was heavily criticised, and this display in Coventry did little to convince they had learned from their errors.
But it was also a night which showed promise for the future as plenty of England’s youngsters grabbed their opportunity to impress, and continue to put pressure on Wiegman's regular starters.
Clinton, who linked up with Manchester United captain Le Tissier to double England's lead in the first half, impressed yet again, while Park and Naz looked comfortable on the international stage.
While England still have plenty of work to do on the road to the defence of their European title, this showed there is an array of talent at Wiegman's disposal - the puzzle remains putting it all together.
Bigger tests are still to come in November with a Wembley showdown against Olympic champions the United States – managed by former Chelsea boss Emma Hayes – before another friendly with Switzerland to end the year.
