England set the tourists a target of 202 to win but South Africa had their top order swept away as they slumped to 6-4 and were rumbled out in 20.4 overs for their joint lowest ODI score against England.
But any advantage they might have had from winning the toss and putting England into bat amid gloomy conditions quickly faded as their top order collapsed. South Africa never recovered with Adil Rashid mopping up the innings and finishing with figures of 3-29. Liam Livingstone top scored for England with 38, contributing in a brisk 43-run partnership for the seventh wicket with Sam Curran as they hauled the hosts from 101-6 to 144-7.