Patient Keaton Jennings finds his subcontinental stride once again

These are the rewards for patience and persistence. Not just the patience and persistence of Keaton Jennings, who took 76 overs - and almost two years - to reach the second century of his Test career, but patience and persistence in him.

By the end of the English summer, it seemed unthinkable that Jennings could be selected for this tour. He had, after all, gone 10 Tests in succession without a half-century - a record for an England opener - and averaged just 19.20 in six matches since his recall. Almost unbelievably, he had averaged just 1.33 against deliveries that would have hit the stumps from seamers in the five-Test series against India and went through a spell of dropping chances in the cordon that hinted at a frazzled mind. Twice he was dismissed leaving a ball and it seemed the selectors would leave him, too.

Jennings admitted to doubts, too. With the pervasive effects of the media - both social and professional - allowing him no escape from the pressures of the job, it got to the stage where he admits he had to "bluff himself" into believing he was good enough to prosper at this level. By the end of day three in Galle, he had everyone fooled.

"When you're waking up at 6.30am, having a cup of coffee and reading about your technical deficiencies, it's not human to say it wouldn't affect you," Jennings said as he reflected on the last few months. "I've been waking in the night panicking, stressing and going through some tough times.

"You read things and that doubt gets created. The pressure gets created to the point where I suppose you wake up and doubt what coffee you're having in the morning. Something as simple as that. So you try to ask yourself 'where is this pressure coming from?' And it's just from a lack of runs.

"You have to keep believing. Whether it's daft of yourself to believe or not, as a sportsman there are times you need to bluff yourself into thinking you're capable of it. The thought did cross my mind during the India series that I might not make this tour."

Ahead of The Oval Test against India, Ed Smith, the national selector, justified Jennings' continued inclusion by pointing out that his average across the English summer was about the same as all the other openers involved in the Test season. And while that was, at the time, broadly speaking correct, it was followed by Alastair Cook making 71 and 147, and KL Rahul 149, in that final Test.

Beyond that, though, Smith pointed out that Jennings' record against spin made a strong case for his inclusion in the squad to Sri Lanka. Jennings had made a century on debut in Mumbai and, while he seems overly-reliant upon the sweep and reverse-sweep (with which he brought up that maiden century), he has not been dismissed in Test cricket playing either shot. Indeed, as CricViz pointed out ahead of this innings, he has been dismissed once every 78 defensive strokes against spin at this level - compared to once every 25 defensive shots against seam bowlers - and never by a ball that turned less than 4.5 degrees.

The ECB system deserves some credit for that. Jennings feels the breakthrough in his batting against spin came when he was sent to the UAE as part of a Lions tour. There he worked on his game with Graham Thorpe and Andy Flower - both fine players of spin themselves, of course - and was subsequently called up to the Test tour to replace the injured Haseeb Hameed. That century in Mumbai followed soon afterwards.

"I suppose I'm going to get slated at some point for playing a stupid reverse sweep," he said. "But I see it as a big strength of mine. I see it as a shot that, in a way, gets me out of jail.

"I think at times on turning surfaces, like day one here, if you play with a straight bat you feel like you're going to nick balls and get out. I felt that reverse sweeping or sweeping was less of a risk."

The team management liked Jennings' apparently equable character, too. While many players - think of Jonathan Trott or, perhaps, Mark Stoneman towards the end of his spell in the side - allowed the inevitable failures that occur at this level to eat away at their confidence, Jennings has the unusual ability to shrug off failures and remain as calm and positive as ever.

That temperament was on display here. There were times he was beaten on the outside edge, but you would hardly have known it: he simply settled for the next delivery and attempted to play it on its merits.

The roots of that calm nature may well have been born in crisis, however. After his first spell in the side ended with him being dropped, Jennings realised he needed to recalibrate his life. He started to appreciate that cricket, while important, was not the only way he should be defined and that there were many joys to be had away from the game. It's not that he doesn't care - far from it - it's just that in order to be at his best, he needed to find a way to release the pressure.

"I felt a lot more happy in my life away from cricket this year compared to last. I didn't feel like the stress of selection was hanging over me all the time" Keaton Jennings after his Galle hundred

"I've been guilty of feeling the pinch in the way I [just] see myself in terms of runs," he said. "But cricket is a job. You do it from 8am until 7pm and then you go home enjoy a beer, a rum and coke and time with your niece and nephew. You spend time with your family and actually have a life outside of cricket.

"I should say a big thank you to the people - my mum and dad, my uncle - who have stuck with me over the last 18-months backed me through some tough times. I felt a lot more happy in my life away from cricket this year compared to last. I didn't feel like the stress of selection was hanging over me all the time. I did the previous year.

"At times, this year and last year, it's kept me sane. It lets you feel stable. Hopefully I can continue to bubble myself in that sort of environment."

There was context, too. Had Cook not retired, had Hameed not suffered a catastrophic loss of form, had most viable alternatives not already been tried and discarded, it seems unlikely England would have persisted with him. But they didn't want to thrust two debutant openers into the fray, they didn't want to force one of their middle-order batsmen into the position and there weren't obvious candidates making irrepressible cases for inclusion.

So, for this specific tour and in these specific circumstances, there was some logic in his inclusion. And the selectors deserve credit for seeing it. This was Jennings third Test in Asia and he has scores of 112, 54 and 146 not out among them.

But a couple of generations of former England batsmen - the likes of Tim Robinson (who averaged 66 after 10 Tests), Alan Butcher (who scored 22,000 first-class runs and won one Test cap), Alan Jones (who made 1000 runs in a season 23 times in succession without winning a Test cap), Hugh Morris (who played two of his this three Tests against a West Indies side containing Marshall, Ambrose, Patterson and Walsh), Kim Barnett (player of the match in his only ODI), Graeme Fowler (final three Test innings: 201, 1 and 69) - could be forgiven for wondering what they might have achieved had they been shown such confidence and support. Jennings knew he was a little fortunate to win this opportunity.

There was little fortunate about this innings, though. While he survived one leg-before shout on 58 that would have been out had Sri Lanka called for a review, he generally looked admirably solid. Putting to one side the aggression that characterised the batting of England's top-order in the first-innings, he settled for crease occupation and the unhurried accumulation that befits a side starting their second innings on the second day of a Test.

There were 59 singles and just six boundaries in his century and, while he did not come down the pitch to the spinners until he had reached three figures, he swept (both reverse and conventionally) with such assurance that it appeared it was sometimes used as a defensive ploy and played irrespective of the field.

Some caution is required, though. There may be several openers in the county game - the likes of Sam Robson (who looks a fine player of spin), Adam Lyth, Stoneman, et al - who would make a century every 10 games or so if given the opportunity. This innings, admirable though it was, does not signal Jennings' arrival as a Test player. No, the players who can sustain a career at this level, have to produce runs with some degree of consistency.

This was a large step forward for Jennings, but he has played 10 Tests in England, not made a half-century and averaged 17.72. Like the sombrero bought in Mexico or the kaftan worn on holiday in the Middle East, what works abroad doesn't always sit so comfortably at home. England won't play three spinners at home; it's possible they won't play Jennings, either.

"This is just a starting point," he acknowledged. "You have to make sure you do it over and over again. Look at Alastair Cook: he scored 33 Test hundreds and played 161 matches yet there were still doubts about his place at times.

"I've got to make sure I put it this in context, come out again tomorrow and continue to try and get better. It's been a tough 18 months, but I sit here tonight really proud."