Let's start with a disclaimer. The opening pair are not the only reason South Africa have struggled in this Test match, they are not even the main reason - this game was all but lost because of Vernon Philander's illness and the inability of the other bowlers to make up for his absence - but they are an issue that needs discussing.

In their last 12 Test innings, South Africa's top two have averaged 12.91 with a best stand of 21. In that time, they have tried four different players: Dean Elgar, Stephen Cook, Theunis de Bruyn and Heino Kuhn. The only thing that is obvious is that Elgar is a keeper. Since January 2015, he has been far and away the stand-out South Africa opener not least because he has played the most matches. He averages over 40, a decent benchmark by anyone's standards and though his style is not pretty, it is mostly effective.

The next question is who should partner him and in South Africa the choices are few. They would be because South Africa is a notoriously tough place to open the batting, Graeme Smith used to call it the toughest in the world and the numbers just about agree. In the last five years, openers average 30.52 in the country, more than five runs less than the global average of 35.96.

Although a less-demanding environment to Tests, it stands to reason that openers who average over 40 in first-class cricket in South Africa must be doing pretty well. That includes Cook (40.03) and Kuhn (44.28), who have maintained impressive numbers over more than a decade and averaged 49.04 and 56.72 over the last two first-class competitions respectively. The only other batsmen in the same league is Aiden Markram, who played six franchise first-class games last summer and averaged 60.11.

Before this series, the selection panel decided Cook was done. Long before. They dropped him for the final Test against New Zealand in March, after he had scored 17 runs in four innings on the tour, but was not the first time in struggled. In Australia, four months earlier, Cook made 35 runs in the first two Tests and his technique - loose outside the off stump and lacking in footwork - came under scrutiny but a century in the day-nigher in Adelaide bought him some time. Cook went on to score another hundred in the home series against Sri Lanka, where he averaged 43.2 before the lean run in New Zealand that cost him his place. And it must cause us to ask, were the selectors too hasty?

Knowing that they won the series in New Zealand because of a rained-out day in Hamilton and a good session in Wellington and not through consistency, they felt some changes were necessary before a big summer in England. The lack of big runs and the absence of hundreds - South Africa only have one century from their last five Tests - suggested the only something they could do was in the line-up and with a reserve middle-order batsmen in de Bruyn already around, the only other something was at the top.

Having decided Cook would not play in the series, the choice was between Kuhn and Markram; between a 33-year-old who has been a consistent performer on the first-class scene and had been overlooked for too long and a 22-year-old, who could become a long-term solution; between rewarding someone who had done their time and deciding it was time to take a leap of faith in someone new. Perhaps out of a sense of duty, but more likely on recent form the selectors chose the former. Kuhn had the better run in the A tour of England, in which he scored a double-hundred against Hampshire and a century against the England Lions, so his ability to get runs in these conditions edged him ahead. But he has been unable to translate that at Test level.

Though his temperament appears hardened, his technique and shot selection has left something to be desired. He has been hesitant to get forward in previous innings, been worked over by Stuart Broad and when he did decide to go on the front foot in the second innings here at The Oval, he was out playing across the line. In his six innings so far, Kuhn has only once faced more than 30 balls. By comparison, in 19 innings, Cook did that 12 times.

So now the question is about the future. Whatever happens at Old Trafford, South Africa will have to decide how they going to tackle the home summer, which is scheduled to include 10 Tests. Are they going to stick with Kuhn, at least early on, and see if he fares better in home conditions or are they going to take the plunge and pick Markram, allow him the time to grow into the role and know that they have someone who could be a feature for a few years? Giving a player a fair run, which includes enough time to see how they perform in different conditions against different opposition could give Kuhn an extended run but all sense would suggest Markram must be the man to take over. If and when he does, he may not solve all South Africa's struggles but it may be a start.

Firdose Moonda is ESPNcricinfo's South Africa correspondent