They have the Caribbean tourists by the short and curlies already, having enforced a follow-on during productive day three and then ripping out two further second-innings scalps before the close of play.
With a formidable shortfall of 275 runs still to make up by the West Indians, there is a strong chance the No 1-ranked South Africa will wrap up the game at some stage on Saturday’s fourth day – especially if they have a fuller bowler complement at their disposal than was the case at times on the scheduled middle day of the contest.
It is difficult to imagine that Hashim Amla’s side will experience any time soon the same degree of disruption they suffered to their XI in the space of a few hours: it began with Faf du Plessis being struck down by a virus overnight and then wicketkeeper-batsman Quinton de Kock rolling an ankle in the warm-up.
But then, almost as quickly as Amla had decided to make the under-the-cosh visitors bat again, the skipper found himself two key seamers down as Dale Steyn and an in-form Vernon Philander interrupted their opening spells to head for the pavilion and treatment for respective ailments.
This meant that part-timers Stiaan van Zyl -- who bowled his medium-pacers with increasing competence – and Dean Elgar suddenly found themselves operating with a newer ball than either has probably ever imagined at this level.
It says much for the Proteas’ purpose and professionalism, on a day when the underdogs sometimes showed better resilience than the scoreboard suggests, that they were able to grab such a stranglehold despite the various drawbacks.
At one stage there was even the novel sight of bowling coach Allan Donald, now 48 and without a first-class gallop in 10 years, making sure he was in full whites in case of emergency deployment as a substitute fielder. They should have asked for volunteers from the South African written press corps; that might have been even more fun.
Still, just as welcome a development was that SA achieved their grip on one of those rare full days in the field where pedigreed main spearhead Dale Steyn went wicketless in all the time he was fit to bowl; a beautifully persistent Philander and sporadically hostile Morne Morkel snared nine victims between them.
Even as there is every chance the hosts will win with a fair bit of daylight to spare at SuperSport Park, there have been some useful lessons to bank as the series shifts pretty speedily onward to Port Elizabeth on Boxing Day.
The interruptions suffered by both Steyn and Philander, in particular, were a reminder that playing only four specialist bowlers (in this instance all of them right-arm fast-medium) is a policy occasionally fraught with peril.
Going willow-heavy was an approach initiated in the tenure of Gary Kirsten as coach and has filtered into the Russell Domingo era, but what people perhaps forget is that until quite recently there had been a Jacques Kallis or (sometimes and) JP Duminy to act as a proper fifth element of the attack from the swollen batting ranks.
With respect, both are in a different bowling league to Van Zyl and Elgar, and if the Proteas go a bowler or two down under current circumstances, they are potentially in a more serious pickle.
They would be crazy to go into the St George’s Park Test without a specialist spinner, so expect Robin Peterson – long in action as a stand-in fielder and presumably frustrated, muzzled bowler on Friday – to get a place in the starting line-up in the Friendly City.
Instead of ditching a paceman to facilitate his inclusion, the brains trust really should come to the realisation that the Proteas are well capable of making enough runs over the course of two innings against this modest West Indies attack with six batsmen, and then the likes of Philander and Peterson taking pretty solid care of positions seven and eight if even needed.
It would endanger somebody like Alviro Petersen, the under-performing opener who is, alas, catching rather better at slip than he is amassing runs.
South Africa’s mammoth first-knock score of 552 for five at Centurion, and quite possibly no need to take second strike, is all the evidence needed for rebalancing the side a tad, isn’t it?
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