Lunch West Indies 251 & 34 for 6 (Da Silva 1*, Maharaj 2-4, Harmer 2-10) trail South Africa 320 & 321 (Bavuma 172, Mayers 3-46) by 357 runs
South Africa are four wickets away from sealing the series against West Indies after setting them a record target of 391 at the Wanderers, an improbable task after a top-order collapse. Instead, West Indies face the prospect of being dismissed for their lowest Test total, which is currently 47.
Kagiso Rabada, who recovered from a back spasm, to play a cameo at No.11, bowled an extended seven-over new ball spell and made the first inroad. He removed West Indies captain Kraigg Brathwaite for the fourth time in four innings in the series - this time lbw with a ball that straightened and beat the outside edge - and then strangled Raymon Reifer down the leg side.
Wiaan Mulder was not available to share the new ball, as he did in the first innings, because he was sent for a scan on his right index finger after being hit while batting on the third day. Simon Harmer opened the bowling from the Golf Course End and found significant turn from his first ball. Harmer looked threatening throughout and eventually found Tagenarine Chanderpaul's outside edge which deflected off Heinrich Klaasen's gloves to give Dean Elgar the catch at second slip.
Harmer thought he had another off the next ball when Roston Chase was given out caught behind but reviewed immediately and replays showed the ball had missed the inside edge and flicked the top of his front pad on its way through. At the other end, Keshav Maharaj took over from Rabada and bowled Roston Chase with his fifth ball to leave West Indies on 26 for 4, 15 minutes before lunch. Instead of consolidating that position. Jermaine Blackwood pulled out a full-blooded swipe against a shorter delivery from Harmer and sent it straight to Temba Bavuma at midwicket.
On the stroke of lunch, Maharaj asked for a review after he beat Kyle Mayers forward defence and hit him on the pad. It proved to be successful but, when taking off to celebrate, Maharaj went down with what looked like an Achilles injury. He was stretchered off the field at the interval, leaving South Africa two bowlers down but with not much to do.
Earlier, South Africa's last three wickets fell for 34 runs in 36 minutes and 46 balls. Captain Bavuma added only a single to his overnight score of 171 before he holed out to deep square leg in the second over of the morning. Bavuma departed to applause from a small but growing Saturday crowd. Maharaj went in similar fashion but not before starting the day with a cracking cover drive off Kyle Mayers.
Rabada then made the most of his licence to thrill. He middled just about every ball he faced and sent a Mayers legcutter and Holder short, slower ball over midwicket and long-on for sixes in successive overs. Holder cranked up the pace three balls later, cramped Rabada for room, and he top-edged a pull to give Holder his third wicket.
Despite West Indies' efficiency in the field on the fourth morning, they still faced a huge task. The highest successful chase at the ground is 310, reached by Australia in 2011, while the most runs ever scored in a fourth innings at the venue is 450, which South Africa put in a draw against India in 2013.
Firdose Moonda is ESPNcricinfo's correspondent for South Africa and women's cricket