Jonny Bairstow scored an unbeaten 49 runs off as many balls as England extended their lead to 364, moving closer to a second innings declaration and setting South Africa an improbable victory target in the first Test at Kingsmead.
England were 7-275 at lunch on the fourth day on Tuesday, losing four wickets but adding 103 runs to their overnight score of 3-172, with Bairstow and Chris Woakes (two) not out.
South Africa off-spinner Dane Piedt claimed a five-wicket haul - the first by a South African spinner in six years - but it was England who continued their dominance of the game by increasing their scoring rate even though they lost wickets.
Joe Root, who was unbeaten on 60 overnight, added 13 to his tally before guiding a Kyle Abbott delivery to first slip to be caught by Stiaan van Zyl.
Ben Stokes followed five runs later as a bouncing delivery from Piedt caught his gloves and went straight up in the air for Dean Elgar to complete the catch.
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James Taylor, seeking to force the pace, came down the track to Piedt but was beaten and stumped by AB de Villiers for 42.
Moeen Ali was Piedt's fifth victim but the lbw dismissal came only after a review having initially been given not out. He made 16 runs.
South Africa, without the injured Dale Steyn in attack, did not take the new ball as Piedt went in search for a fifth wicket and the seamers looked for a some reverse swing.
Steyn will not bowl again in the Test after his shoulder spasm failed to clear up overnight, officials said before Tuesday's play.
He was still experiencing discomfort after pain restricted his bowling in England's second innings on Monday.
A scan on his right shoulder revealed no tear but with the second test in Cape Town to start on Saturday, South African team management were obviously taking no chances.
