This is the age of the super analysts, who can churn out data to prove just about anything. Yet there may not yet be a formula that takes into consideration the impact of cricketers being afflicted by a flu epidemic before and during a Test match. No doubt some wizard is working on that right now. In the meantime assessing England’s performance at Centurion is a puzzling operation.

Only the most ruthless of observers or the most blinkered would give the team no leeway after their defeat to South Africa in the first Test. It is tough enough trying to avoid splitting the odd infinitive when beset by flu let alone bowling with a shortage of oxygen in temperatures in the mid-30s or batting against 90mph projectiles.

The daily lurgy update from the England and Wales Cricket Board’s indefatigable press officer, Danny Reuben, revealed another victim on Monday, Dom Sibley, who has become the 11th player to be afflicted.

It is now quicker to identify those who have so far avoided the bug: they are Rory Burns, Zak Crawley, Jonny Bairstow, Jimmy Anderson, Sam Curran and Matt Parkinson, plus the two latecomers, Craig Overton and Dom Bess, and it is unlikely any of them are taking their good health for granted. The good news is that Chris Woakes and Jack Leach are no longer in quarantine and will soon be in Cape Town.

England have said they are not hiding behind the epidemic. Every reaction to the defeat begins in the same way. Chris Silverwood, whose honeymoon period as coach has been all too brief and trickier than anticipated, delivered the standard line before elaborating.

“I want to make it very clear we can’t use it [flu] as an excuse for some of the things we could have done better”, he said before adding, “We’ve seen a lot of character, a lot of guts and a lot of bravery from a few of the guys who have been poorly but have got themselves out there. I’m proud of the guys in that respect, the amount of courage that they’ve shown. Equally I don’t want to take anything away from South Africa, I thought they played well at times. There are certain things we have to learn from as well going forward”.

It is hard to argue with the last observation. As well as being just ill, England were ill-prepared through no fault of their own but they were also ill-disciplined with the ball and profligate with the bat in their first innings. Wherever you look at the team there is scope for improvement and, assuming the epidemic subsides, there are some very tricky decisions to make before the second Test at Newlands that begins on Friday.

As any self-respecting coach is wont to do Silverwood latched on to the odd positive. “The opening partnership between Burns and Sibley [in the second innings] was superb and it gave us some hope”.

No doubt Sibley has done enough to retain his place, illness permitting, and he was impressively calm and stoic at Centurion but reservations remain. I’ve been looking at the data, you see.

Sibley’s output for Warwickshire was undoubtedly formidable last summer, over 1,300 runs at an average of 69. However his career strike rate is unusually low for a prolific batsman; it is 41. Most successful Test batsmen of the modern era have had the capacity to dominate bowlers at county level rather than just wearing them down and this is important for a simple reason. In Test cricket the bowlers are better and more accurate. So where do the runs come from?

The Sibley sample is small but his strike rate at Test level is 28. Already they know where to bowl at him – outside off-stump and most definitely not at his legs. And so the torment begins. By comparison Nick Compton had a strike rate of 46 in first-class cricket, 36 in Test cricket and an average of 28; Joe Denly has a strike rate of 55 in first-class cricket, 41 in Test cricket and an average of 31. County blockers have to work incredibly hard for their runs at Test level.

Sibley remains Burns’s anticipated partner for Cape Town. Ollie Pope, now recovered from flu, is likely to replace Bairstow. But what of the bowlers? Now it really does get ticklish. England have evolved a disturbing tail. They have not quite sunk to the Mullally, Tufnell, Giddins nine, 10, jack of 1999 but it is hard to imagine the current final trio lasting much longer. This is a problem. So too is the question of whether to play a specialist spinner in Cape Town.

Bizarrely the likeliest spinning candidate at present is Bess, who was not in the original squad. Leach, laid up for the last fortnight, is unlikely to be fit and Parkinson feels like an indulgence in such serious times.

But if they want a spinner, who steps down? In all probability it is one of the old guard. Bess for Broad? Bess for Anderson? These feel like surreal alternatives. This was what Silverwood was referring to when he said: “If there is a big decision to be made, we’re not afraid to make it.” The honeymoon really is over.