On Saturday night Joe Root may have wasted much time contemplating the timing of his declaration.
Having a handy lead of 97 runs in the first innings, England were boosted further by the news that Philander will not come to bowl for the rest of the day. And spare a thought for the freelancing stewards.
But with the ball turning exclusively into the two left-handers, their prod-and-sweep methods were productive if rarely pretty until Jennings succumbed to Morkel when he got an inside-edge behind off the back foot.
With the pitch offering increasing turn and uneven bounce, it would be a huge surprise if England do not force victory sometime before tomorrow evening.
The Proteas will be hopeful for a positive result from the scan, with the team already facing a second Test at Trent Bridge next week without strike weapon Kagiso Rabada. Batting was tricky but not quite as tricky as the scorecard suggests.
Root had turned to his spinners early on and, with the surface hinting at variable bounce and increased turn as it cooked under the sun, they will doubtless have an even greater role to play later in the game. How they repaid him.
The Yorkshireman rode his luck early on in his innings and was lucky to avoid being caught in the deep on five and was then dropped by JP Duminy in the gully for just 16.
Thirteen balls later Elgar was on his way for two when Moeen took a hard-hit return catch.
On another balmy day they were tormented by two of England's all-rounders, neither of whom was Ben Stokes. Temba Bavuma fell to Moeen Ali in similar vein in the next over. He could not have hoped for a better start to his reign.
Here, Press Association Sport takes a look at the other five top-scoring England Test skippers on debut. Morkel was eventually rewarded for a probing spell after tea as Jennings wafted flat-footed to be caught behind.
JP Duminy, who wears the look of man bereft of any confidence, played an ugly and nervy innings, and having gotten off the mark with a neat clip through the covers then played an bad pull shot, hitting the ball straight to Moeen at square leg.
Next, Rabada intervened with that shooter to Stokes, after which a high full toss splattered the stumps of Dawson for his third consecutive Test duck.
Root said he was delighted by his first victory in charge, which he owed much to the runs scored by England's top three in hard circumstances on Saturday night.
His partner enjoyed a little more fortune, seeing Moeen spin a ball behind his legs but over the stumps on 2 and surviving a review against Mark Wood on 31, when the ball was shown to be only clipping leg stump.
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