England's high-risk strategy has worked. It has not been faultless, and in two of the three matches so far in this splendid series it might have been derailed. But it has survived, like England, by the skin of its teeth.
To field six batsmen and four bowlers was never at the forefront of the selectors' minds when these tourists came to South Africa. That much was evident from the composition of the squad, which was light on batsmen with no reserve specialist openers. It was pretty obvious that a policy had been conjured up for a bits-and-pieces, belt-and-braces side.
In the days leading up to the First Test, barely before, there was a change of heart. It occurred more forcefully then than before that, on the sort of pitches they were likely to encounter, England might well need six batsmen and that four bowlers might just do the job of taking 20 wickets.
There will be no going back now. If four bowlers can work anywhere it is at the Wanderers, where the Fourth Test begins on Thursday. The nine previous matches have all produced victory for one side or the other, only four times for South Africa. Rain – and there is some about, there always is in Johannesburg – is all that can induce the third draw of the series.
England cannot now lose the rubber and they may once have settled for a tied state of affairs. Having hung on courageously twice, they would be deeply disappointed to be denied now. Six batsmen will be required at the Wanderers, as they were at Newlands last week.
Had there not been a sextet, the match would have been done by tea. It might have been over in any case, it is worth remembering, were it not for the Decision Review System, which has come into its own in the past few weeks. To the first ball of his innings, before an hour of the fifth day had elapsed, Paul Collingwood was given out caught at slip.
Without recourse to a review he would have had no choice but to walk and England, make no mistake, would have had it. But Collingwood immediately made the now-familiar sign to the umpire of a horizontal arm across the bat. The replay was conclusive. The ball had missed Collingwood's bat and brushed his thigh pad. He was spared, England were spared.
In the old days of just before the end of last year, everybody would have grinned and borne it after South Africa's victory in those circumstances. It was the way the cookie crumbled, it would have been said. But England would still have lost a match they went on to save. Cookies do not have to crumble that way any more.
Both teams have benefited. Before Graeme Smith's magnificent second innings had taken real shape he was given out lbw. He referred it to higher authority and went on to make 132 more runs.
"We all know it would be nice to have a fifth bowler but at the moment this is the balance that we think is best for the team," said England's coach, Andy Flower. "That might change in six months' time or even in the next Test. But we will try to make honest decisions with good intent, and that intent is to win the Test match."
England will almost certainly pick an unchanged team for the fourth successive match. It could be the time when Jimmy Anderson swings himself into the series, though he must have horrid memories of the Wanderers. While Matthew Hoggard was taking 12 wickets in a memorable last-day England win five years ago, Anderson, in his only match of the series, was all over the shop in taking 2 for 117 and 0 for 32.
South Africa will have to make changes, but not as many as they might have wished. They suffered the embarrassment yesterday of having to withdraw the 30-year-old Pakistan-born leg-spinner Imran Tahir from their squad because it turned out that he is not eligible. Although no full explanation was given, it seems that Tahir has not served enough qualifying time in South Africa under international regulations.
The 20-year-old left-arm fast bowler Wayne Parnell, who is out of form, may play as part of a pace blitz led by the hugely impressive Dale Steyn, which England can resist one last time.