Close of play report: England 357-5
Many of the 80 men who have captained England in Test cricket have performed as if restrained in a straitjacket. Not Joe Root. The man elected to succeed Alastair Cook when the Essex opener decided he'd had enough five months ago found the position a perfect fit and records tumbled as England made a superb start to the four-match series.
Root batted most of the day for an excellent undefeated 184, becoming the fourth highest scorer in history on Test captaincy debut and the highest scorer among new England skippers. He hit 21 fours, complemented by a beautifully driven six down the ground towards the pavilion, and if he rode his luck at times - he was dropped twice and stumped off a no-ball - his brazenness and impish grin meant few could resent him.
It was a day, really, when Root could do no wrong, from the moment that he called the right way at the toss to the final overs of the day when the new ball taken by South Africa to breathe fresh life into a tired attack disappeared with remarkable regularity off the meat of his bat to the boundary in front of the Tavern Stand.
That said, the incumbent would have been entitled to think the more things change, the more they stay the same when he found himself in the familiar position of wickets falling before and around him to the extent that, having taken first use of a firm but green-tinged pitch, his team slumped to 17 for two.
It was the wicket-to-wicket talents of Vernon Philander rather than the steep bounce of Morne Morkel or irresistible promise of Kagiso Rabada that did the initial damage. Philander lured Cook into a fish outside off stump that sent a comfortable edge into the hands of Quinton de Kock. The ball seamed away from the left-hander but was short enough for the former England captain to have ignored. Soon, Keaton Jennings had gone too and, not long after him, the recalled Gary Ballance as well as Philander became the beneficiary of two bewildering errors in judgment.
First, the 32-year-old pace bowler pitched one on a good length but centimetres outside the leg stump and it moved further, up the slope into the pads of Jennings, opening in only his third Test and his first in England. The left-hander failed to lay a bat on it and although it was clearly passing down the leg-side, even at full speed, Philander's appeal was upheld by umpire S.Ravi.
Jennings asked Ballance, batting at No 3 to enable Root to drop down his more favoured four, whether he should review and the observation of the Yorkshire captain was that he should not. It was an incomprehensible judgment. When Ballance himself was trapped more obviously in front by Morkel from round the wicket, he equally inexplicably called for the ruling of the third umpire. It was a review wasted.
In truth Ballance batted encouragingly enough on his return to the Test fray, one lovely boundary teased through extra cover, but the fact that he was once more caught deep in his crease will not have endeared him to those who thought he was fortunate to get another chance.
Root had announced himself in attacking fashion, uppercutting off Rabada to third man to get off the mark but his desire to attack could so easily have gone against him. His top-edged hook off Rabada should really have brought another wicket but Aiden Markram, on as a substitute at long leg, had wandered in too far and his leap was insufficient as the ball dropped over him and in front of the boundary for an embarrassing four.
Rabada was disappointed a second time when Root flashed at a wide one and was spilled in the gully by JP Duminy. Root was on 16 at the time. By lunch he had moved on to 33 but he lost another partner in the shape of Yorkshire team-mate Jonny Bairstow, leg before to the returning Philander, with the score on 76.
Philander finished the session with 3-26 from eight overs to the delight of Dean Elgar, the stand-in captain in the absence of Faf du Plessis, and the 36th man to lead South Africa in Test cricket.
If the first session belonged to South Africa, the afternoon was all England's. Root continued to bat in the style we have become accustomed to, mixing those pugnacious forces off the back foot through gully with clips and shovels between mid-wicket and mid-on, one of his heaviest scoring areas, topping it all off with wonderfully manipulated cover drives.
As the ball softened, and, inexplicably South Africa left the morning's destroyer, Philander, kicking his heels in the outfield, Root moved serenely to a 28th Test fifty, his only moment of concern coming when Kagiso Rabada clocked him on the side of the helmet as he got through a short ball far too early.
Root knew he had not connected but as the ball ballooned up into the waiting hands of the slip cordon, South Africa were convinced he had edged it first and when umpire Paul Reiffel concurred with the batsman, they went straight upstairs for adjudication. Rabada was again left feeling it wasn't his day as the ruling, rightly, went in favour of the Yorkshireman, although there was suspicion that the bowler had overstepped in any case.
Rabada, 71 wickets from 17 Tests prior to this one, was sanguine enough and gifted enough to know the fates were likely to turn in his favour before too long and he was right when, shortly after tea, Ben Stokes, having completed a responsible fifty himself, swatted at a bouncer from the quickie and feathered through to De Kock.
Stokes had done an excellent job in helping Root consolidate after lunch although there was always the sense that we were experiencing the calm before the afternoon storms that were promised by the weather forecasters before, with one look at Keshav Maharaj, he strengthened from fresh breeze to category one hurricane.
In the modern vogue of not allowing slow bowlers to settle, he went after the left-arm spinner almost immediately, lofting him down the ground for six and trying again in his next over when the hapless Duminy chased vainly for one over his shoulder that he ultimately kicked over the boundary.
Stokes had added 114 with Root before he was out - in truth he was lucky to survive being bowled off a no-ball by Morkel on 44 - but at 190 for five, the game was back in the balance.
Root pushed on seemingly unperturbed, going to what seemed like an almost predestined hundred with a deft dab sweep that brought him three runs. And with Moeen Ali finally finding his range after 16 scoreless deliveries, he was untroubled until on the brink of his 150 when he skipped gaily down the pitch to a previously unimpressive Maharaj and was surprised to find himself stranded by one the bowler threw wider and turned prodigiously. De Kock had two attempts at flicking the bails off but South African relief turned to anguish when it was revealed that a bowler had overstepped again.
Root had the common decency to laugh embarrassedly at his good fortune and in tandem with an increasingly elegant Moeen, brought up that 150 before making hay against the new ball.
It was a chastening day for the tourists in which Rabada and Morkel, who still found nip off the seam late in the afternoon to beat Root a couple of times, showed promise of better things ahead, while Philander showed exactly why he has an average of 22. But there must be suspicions over his fitness - otherwise it is hard to fathom why he bowled only three overs between lunch and the taking of the new ball.
By the time he had the new cherry in his hand, South Africa had long lost their early intensity.
FUN FACT: England and South Africa's first captains, James Lillywhite and Owen Dunell, died within four days of each other in 1929.
TEAM NEWS: Liam Dawson was included by England as a second spinner who can bat a bit in preference to a fifth seamer in Toby Roland-Jones while Heino Kuhn was named as Dean Elgar's opening partner for the tourists. Theinus de Bruyn, the fastest South African to 1,000 first-class runs, was included to bolster the batting at the expense of all-rounder Chris Morris.