Jofra Archer took six wickets as England beat the Proteas by 59 runs in the third ODI at the Diamond Oval in Kimberley on Wednesday.
Dawid Malan made 118 and captain Jos Buttler 131 in an England total of 346-7, before South Africa were bowled out for 287, with fast bowler Archer taking a career-best 6-40.
The Proteas had already clinched the series by winning the first two matches but Buttler said Wednesday’s win was a reward for the hard work his players had put in during the short series.
“There’s been some really good stuff. Guys getting hundreds and Jofra Archer was brilliant. We’ve got a good thing going. We’re building nicely,” said Buttler, who was named Man of the Match and Man of the Series.
Proteas captain Temba Bavuma said the series win was important.
“We came in under a lot of pressure. We’ve done ourselves justice and come closer to automatic qualification for the World Cup.”
The Proteas need one win in their remaining two matches against the Netherlands to move ahead of the West Indies into one of the eight qualifying places in the World Cup Super League, although Sri Lanka could still move ahead of them in a forthcoming series against New Zealand.
The left-handed Malan and his right-handed captain shared a fourth wicket partnership of 232 off 211 balls after coming together with their team in trouble at 14-3 in the sixth over.
A slow start to the partnership became a torrent of runs as they took command on a slow pitch.
England scored 217 runs in the last 20 overs of their innings, scoring rapidly even after the two centurions were dismissed.
The Proteas opted to go into the match without their two fastest bowlers, Anrich Nortje and Kagiso Rabada, and appeared powerless to keep the scoring in check.
When South Africa batted they were 59 runs ahead on comparative scores after 30 overs. The difference was that England had more strike power in the middle overs, with Archer and leg-spinner Adil Rashid (3-68) taking crucial wickets.
Archer, in the second match of an international comeback after a long injury-enforced lay-off, bowled consistently at speeds of more than 145km/h.