South Africa 175 and 117 for 4 (Elgar 72*, Bavuma 16*) need a further 375 runs to beat England 353 and 313 for 8 dec (Bairstow 63, Westley 59, Root 50, Maharaj 3-50)
The word on the streets after South Africa's victory at Trent Bridge (or on social media at any rate, the meanest streets of all) was that England were a soft touch and could learn a thing or two from the resilience of their opponents.
Such reputations have been dismantled at The Oval, where England will enter the final day only six wickets away from a victory that would put them 2-1 up in the series with one to play. It is England who have had bristled with intent with bat and ball while South Africa's top order has crumbled twice in the match against insistent seam bowling on a surface which has always kept the bowlers interested.
South Africa were up against it in the first innings in devilish batting conditions; the English summer at its most cantankerous. On the final session of the fourth day, with the weather fresher and breezier, mitigation was a little harder to find - unless it was the intimidating presence of their target of 492 to win, a target never previously achieved in Test history, or, more realistically, the need to survive for four sessions.
They slipped to 52 for 4 by the 16th over. All England's quartet of pace bowlers carried a threat, unlike South Africa. Morne Morkel has looked on the verge of something special all summer, but has only one Test left to be rewarded. Chris Morris has gone for nearly six an over in this match. The left-arm spin of Keshav Maharaj was under-used. As for Vernon Philander, he was still under the weather and incorporated 15 overs in his toilet breaks.
Only Dean Elgar assembled doughty - and, at times, painful - resistance with the bat for South Africa, as he battled his way to an unbeaten 72, Temba Bavuma offering support in an unbroken stand of 65. Elgar will check his left hand gingerly on the final morning. He habitually taunted the slip cordon with his angled defensive pushes and when he did nick one, on 9, Keaton Jennings fumbled low to his left.
England have even sorted out their previously incompetent methodology on umpiring reviews, replacing the Who Shouts Wins technique with a more rigorous discussion in which Root, from afar, seems to be asking pertinent questions and Jonny Bairstow, the wicketkeeper, has a central role.
A lot of attention has focused on Jennings' unproductive series at the top of England's order, but Heino Kuhn has fared no better. His debut series has brought 78 runs at an average of 13. He survived Stuart Broad's big appeal for lbw thanks to a big thrust forward, only to be cleaned up in Broad's next over.
Hashim Amla remains the prince of wickets: Toby Roland-Jones has given him both barrels, caught at the wicket in the first innings, held by Root at second slip on this occasion. He was happy to walk, but the umpires insisted, somewhat unnecessarily on checking the validity of the catch, the sort of things umpires do when world-renowned batsmen are dismissed by a relative unknown.
Then came two in two for Ben Stokes, who has looked more of a threat here. A yorker did for de Kock, hitting his boot on the way, although the umpires might have taken a longer look at the marginal no-ball, and Faf du Plessis was lbw first ball to a leave-alone, confirmed on review. South Africa's captain, an inspiration in Nottingham, has made 1 and 0 and left them both at The Oval.
One small word of warning for England: when South Africa batted for 148 overs to draw against Australia in Adelaide five years ago they were four down at stumps with a day remaining. But this is not an Adelaide pitch. And on that occasion South Africa had AB de Villiers, Jacques Kallis and du Plessis on hand.
Root's first declaration as an England captain had been a conservative one, at 313 for 8, but he would have rested easy at the close and the weather forecast was good for the final day.
England received little charity from the South African attack as they moved gradually to a tea-time declaration. Only when Bairstow, with a run-a-ball fifty, and a twisted ankle in the process, emerged in mid-afternoon did England find a final dash. He added 49 in eight overs with Stokes, who planted Morris into the stands at cow corner before Morris struck his stumps later in the over as he attempted further mayhem.
An abstemious maiden Test fifty by Tom Westley was the centrepiece of a heedful morning. Westley only contributed 22 out of 79 to England's total in the session, but there was again a grace in his game that made him eminently watchable even when not scoring quickly.
Some batsmen, such as Stokes, encourage roars of approval; cheers for Root are sourced in admiration; Westley, if he prospers, will bring sighs of pleasure.
Maharaj then intervened with two wickets in successive overs early in the afternoon. He spotted Westley's advance down the pitch, on 59, and found enough turn to beat his outside edge for de Kock to complete the stumping. Root also reached 50, but then swept him to deep square.
Dawid Malan is as off-side dominant as fellow debutant Westley favours the leg side. His second-innings dismissal carried a reminder of what had gone before. Then he was cleaned up by an inswinging yorker from Kagiso Rabada. He again fell prey to the ball coming back sharply into his pads, falling lbw to Morris, a wicket only won by South Africa on review.
As Root opted for a safe lead then more some, Moeen Ali was run out by a direct hit at the non-striker's end from Bavuma, who dashed in in from deep midwicket as Moeen sauntered a second run. Toby Roland-Jones then had some fun larruping Elgar's left-arm slows - a debut full of smiles.
Jennings' England career is under scrutiny. He is without a Test half-century in six knocks. He added 14 on the third morning, but his two boundaries off Morkel were unconvincing, thick edges. Rabada surprised him with a bouncer, on 48, and won a lobbed catch to gully off the glove.
Rabada has the capacity to bowl an excellent shock ball whether it is the sort of yorker that unhinged Malan in the first innings or the bouncer, by far the shortest ball he had bowled in the England innings, which removed Jennings. Nevertheless, Jennings' statuesque style is bound to be bringing growing concern for England's selectors ahead of an Ashes tour in Australia this winter.
Westley had challenges of his own to contend with. It has not taken South Africa long to cotton on to his strengths. Indeed, such is the constant analysis of a new England player that it would have been no surprise if a Romanian plasterer had wandered up to him on the platform at Bank as England travelled to the game by tube and said: "You must be Tom Westley, the one with the strong leg-side game."
Resuming on 28, under overcast skies, he did not bring up his first Test half-century until 10 minutes before lunch, courtesy of the shot that he must have been aching to unveil all morning, a graceful clip through midwicket against Morkel that, as much as any other shot in his armoury, exudes quality. There was enough time in the game for him to play in restrained fashion and he had the intelligence to do just that.