In England's first outing since their disastrous T20 World Cup group-stage exit in October, they played with a more reserved style than the ultra-aggression that head coach Jon Lewis has tried to encourage.
But wins are the most effective form of currency in silencing critics and they managed that comfortably - starting with a solid, if not spectacular, all-round bowling performance.
Their only specialist seamer Lauren Bell did struggle, conceding 46 from her four overs, and leg-spinner Sarah Glenn also had difficulty in finding rhythm but Ecclestone and Dean were back to their best after tricky individual World Cup campaigns.
Dean claimed the big breakthrough of South Africa skipper Wolvaardt, deceiving the opener with a well-executed quicker ball, and then had experienced all-rounder Luus caught at mid-off.
Ecclestone's sole wicket was of opener Brits, who was stumped, but she conceded just 18 from her four overs and her swagger of confidence had returned - a sight that will certainly please England fans.
At 64-4 and with most of their senior batters back in the dugout, South Africa seemed destined to collapse but the spirited Dercksen ran brilliantly between the wickets to accumulate vital runs in a stand of 36 with Nondumiso Shangase, before De Klerk gave the Proteas a decent total with four fours in her entertaining cameo.
There were still a few fumbles in the field, and Sciver-Brunt dropped a simple catch off Bosch on 13 - it ultimately only cost a further five runs, but those are the small errors that England will be hoping to put right throughout this multi-format series and before the Women's Ashes start in January.