Years ago, while going through something of a slump in his long and admirable career as an opening batsman, Kim Barnett - of Derbyshire, Gloucestershire and, for a while, England - found himself cursing his poor luck in receiving a succession of excellent deliveries.

But then he realised that such a fatalistic attitude was part of the problem. It allowed him to abdicate responsibility for the failures and prevented him from searching for solutions. In short, Barnett concluded that, if you find that you keep receiving unplayable balls, you're probably in the wrong job.

It was an episode that came to mind when watching Keaton Jennings in the second innings at The Oval. Not for the first time, it seemed Jennings was the unfortunate recipient of a fine delivery. Mohammed Shami, having taken a few away from the left hander, went wider on the crease from round the wicket and persuaded one to seam back sharply and take Jennings' off stump as the batsman shouldered arms. It was, no doubt, a good delivery.

But that shouldn't be any surprise. This is Test cricket. And while the national selector, Ed Smith, no doubt has a point when stating that it had been "an extremely difficult summer to open the batting in" during an interview with the BBC's Test Match Special - Alastair Cook is the only opener on either side to have made a half-century in the series - you wonder if he is not falling victim to the same sort of fatalistic passivity that Barnett slipped into for a while.

Has this series really been more demanding for an opening batsman than others of the recent past? Has it, for example, been more demanding than that experienced by Michael Carberry, in Australia in 2013-14, when he spent several weeks trying to see-off Mitchell Johnson and Ryan Harris at their best?

Has it been more difficult than it was in 1984 when Graeme Fowler and Chris Broad were asked to see-off Malcolm Marshall, Joel Garner et al?

Or even more difficult than Cook and Mark Stoneman found it in Auckland earlier this year when Trent Boult and Tim Southee were nipping the ball around masterfully? Or in Perth, when Mitchell Starc, Pat Cummins and Josh Hazlewood were bowling with pace and hostility?

Opening the batting in Test cricket is always tough. Pointing it out is like an ice skater complaining the rink is slippery.

The statistics of Jennings' career are damning. No England opener has ever gone as many consecutive innings (18) without a half-century and, against deliveries from seamers that would have hit the stumps in this series, he is averaging just 1.33. Those are figures that wouldn't flatter an inanimate object. This was the second time in successive matches that Jennings had been out leaving a ball and he has been moved out of the slips having dropped a couple of relatively straightforward chances.

Keaton Jennings is bowled after shouldering arms to an incoming delivery Getty Images

While the England management have been impressed by Jennings' calm demeanour - and it is true, he does appear to be an admirably equable character - you wonder how deep his reserves of self-confidence can be. He's now played 10 Tests in England, after all, and he has a top-score of just 48. His career average - 22.09 after 12 Tests - is boosted by a drop before he had scored on debut. Had it been taken, it would be averaging 17. These are not small sample sizes. He would be almost inhuman if he was not beset by self-doubt.

And to think, it's not so long since a player with an outstanding record was dropped - in part, at least - for whistling as he walked back to the dressing room after his dismissal or looking out of the window during a team meeting. Oh, to have such an embarrassment of riches now.

Yet all the hints suggest Jennings will be part of the England squad to tour Sri Lanka. Not only did Smith suggest it in that BBC interview but, at the close of play, England's assistant coach, Paul Farbrace (who, it should be noted, is not a selector) reiterated it.

"I'd like to think he's done enough in difficult situations to be opening the batting come the first Test in Sri Lanka," Farbrace said. "I'd like to think the selectors would stick with Keaton.

"It's been tough for anybody at the top of the order against the new ball. And he's played two important innings in this game to help us not lose early wicket and to give us a chance of getting a score. The one thing that has been impressive: you'd never know looking at him that he hasn't scored the runs he would have liked."

In many ways, England's consistency of selection is an asset. It helps create a settled, selfless environment and gives players the best chance of optimising their ability. Nobody is advocating a return to the days when 29 players were used in the 1989 Ashes series and players were looking over their shoulders at all times.

But there is a downside. England's stubborn refusal to accept the evidence in front of them has led to the somewhat absurd situation where Jennings is likely to go to Sri Lanka simply because the team are reluctant to blood two new openers at the same time. Had they been a little less passive - or, perhaps, a little more humble in admitting their error - they could already have blooded the likes of Rory Burns who has just reached 1000 first-class runs in the season for the fifth time in succession. Jennings, by contrast, failed to reach 50 in 20 successive first-class innings after he was dropped by England in August 2017. He was recalled averaging 26.18 in first-class cricket since his previous Test.

Even now, there is no guarantee that Burns will tour. Instead the selectors are understood to be giving serious consideration towards the call-up of Joe Denly. It would be a remarkable selection, really. Not just because Denly is 32 and uncapped or because he plays in Division Two, but because he hasn't even been opening the innings. While he has moved up to No. 3 for the last couple of Championship matches - in one of which, against Derbyshire, he has made a century - he has generally batted at No. 4 in recent times.

The irony of all this is that Smith was appointed amid talk that he would apply statistics to his selection in a far more scientific manner. Instead he seems to be ignoring statistics, facts and even logic. England settling for a batting average of 1.33 from their opening batsmen against straight deliveries seems to be setting the bar terribly low.