Curran was the pick of the bowlers with three wickets, while Liam Plunkett snapped up two, and Dawson, David Willey and Chris Jordan chipped in with one wicket apiece.
"The players that have come in are a bit younger than we have had in previous years but, looking ahead to the 2020 T20 World Cup, it's good to blood these guys now as hopefully these will be the players representing us then".
Meanwhile De Villiers was left to rue some sloppy fielding as his side, beaten in a one-day global series by England and knocked out in the first round of the Champions Trophy, suffered another defeat on this tour. "We let it slip there".
In reply, England got off to a brilliant start in their run chase despite losing Sam Billings for three off the bowling of Morris as they got to 51-1 after the powerplay.
It had been a strong bowling performance from South Africa with seamer Chris Morris, who removed the unsafe Bairstow after picking up opener Sam Billings early, providing pace and fire in his spell of 2-18 from four overs.
His exit brought in Malan. But when Bairstow lofted to mid-on and Roy was given out a few deliveries later, South Africa's seamers - enjoying a track offering pace and bounce - turned the screw in expert fashion amid failing light and mounting excitement.
Hales had reached eight when he was struck on the knee by Paterson and left in a crumpled heap on the floor.
"We lost the two "in" men with Jason getting out, and no one took up the reins which is disappointing".
The stand was broken when Hales (36) holed out to deep midwicket where David Miller took a good catch and Malan fell soon afterwards, caught at long-on off Tahir.
England dropped three catches before Curran stole the show with two more wickets in the penultimate over of the innings.
Even though the Proteas began to lose wickets in a hurry after De Villiers' departure, Farhaan Behardien's quickfire 32 enabled them to finish on 174/8 off their 20 overs.