It was the stillness that was the most startling factor. In a match marked by frenetic, frustrated, insincere application from the vast majority of England's batters, here at last was a combatant who had found the headspace to meet the ambition of his strokeplay.
It took one final scare to get him there, though.
Jamie Smith had been a largely blameless, passive presence in the course of his first 15 runs from 31 balls. His innings had begun as Joe Root's had ended - which, at 66 for 4, was a very real indication that the tide was turning against England. And, as three more batters encountered the nemesis that their first-innings hubris had ordained, Smith faced up to Milan Rathnayake for the start of the 27th over, with the scoreline reading a do-or-die 84 for 7.
His next shot was the last false one he would play. It was also the first ball he had faced for a full 17 deliveries - a passage of play marked by Sri Lanka's strange switch from the full-length swinging hostility that Vishwa Fernando in particular had epitomised, to a bang-it-in show of machismo against Olly Stone that may or may not have related to Stone's earlier bouncer to Lahiru Kumara, and the choice words from Asitha Fernando that had followed it.
Either way, Smith had sensed his moment, and he made it his mission to seize it. He charged his next ball, from Rathnayake, and nearly fluffed his lines as a full-length outswinger skimmed off his leading edge just out of reach of mid-off. But unlike so much of the distinctly average fare from his colleagues up the order, Smith's cricketing instincts had not deceived him. As Sri Lanka approached the end of their finest hour of the series to date, they allowed their eyes to stray momentarily from the prize, and a 24-year-old in the sixth Test of his maiden summer was primed to strike.
"It's exciting when he comes in, isn't it?" Paul Collingwood, England's assistant coach, said afterwards. "It's amazing watching a guy who reads situations so well, and is able to bat with the lower-order in the manner that he does. He's going to put a lot of teams under pressure when you've got those skills, and the power that he has."
Smith's next shot was far cleaner - a bit of width, and a lasered slice through point - while his fierce pull over midwicket evoked his roof-clearing efforts at Trent Bridge and Lord's. But it was his third boundary in four balls off Rathnayake that announced his innings had arrived. Notwithstanding the ramps, scoops and assorted hoopla that had made Ben Duckett's first-day 86 so captivating, nothing could compare with the cleanliness of Smith's lift through the line over mid-off.
It was the apogee of a 36-run assault in the space of 12 balls that powered him through to a 43-ball fifty, and ensured that England still have something to play for on Monday. And notwithstanding the fact that Pathum Nissanka had trumped him by the close in his own gleeful knock of 53 not out from 44, Smith's response to a moment of genuine crisis - arguably the first of England's hitherto dominant summer - was so instructive that Collingwood had no compunction about uttering the G-word in assessing the impact he's already making, after a maiden summer in which his 487 runs are already the third-most by a England wicketkeeper in a home Test season.
"You go back to the days when Gilchrist used to come in at No. 7 for Australia," Collingwood said. "It sucks the life out of you as the opposition, when someone has the ability to do something like that. He's shown in his short Test career some great skills and he's certainly an entertainer. You could see everybody in the crowd, just wanting and willing that partnership to carry on."
It is typical of this England team to fight hubris with hubris. On a day when Harry Brook in particular was bent over Mother Cricket's knee and given the spanking that Michael Vaughan had warned him was coming, Collingwood ensured that Smith will rock up to Perth in 12 months' time as Australia's most gargantuan tabloid target since Stuart Broad in 2013-14.
But that's how this England team rolls. If you're not 'running at the danger' and attempting to launch it on the up over extra cover, you're not living. And though much of Collingwood's subsequential spiel about "doing something special tomorrow" was straight out of the Bazball playbook, there was no way to fake the excitement in his voice as he threw ahead to a contest that could be all over by lunch.
What an extraordinary means to manufacture some jeopardy though. With the greatest respect to Sri Lanka's fighting qualities over the past two days, England played their first innings like a bored '90s teenager on Cricket Captain - auto-complete innings, let's get to the sharp end - then started their second in an identical vein, until Vishwa stopped them in their tracks with the most genuine injection of quality in the contest to date.
Duckett and Ollie Pope had been magnificent in their own ways, of course - Pope in particular after his well-documented struggles. But until that pair of inswingers thudded into the shins of Joe Root and Brook, England had lost each of their first 13 (thirteen!) wickets of the match to attacking strokes, as if England runs and wickets had hitherto been subject to some ancient bartering system: a cartload of turnips (on a good length outside off, please) in exchange for 11 turkeys and a pair of hog-roasts.
Assistant coach Paul Collingwood speaks about Brook's season, in which he has scored one century and two fifties
This time, Dan Lawrence attracted the best price, as he strove to hit his way back to form, and very briefly seemed to be winning the battle against his better judgement. Instead of holding his own outside off, in the manner expected of a Test-match opener, Lawrence reverted to open-faced slashes over the covers like the Chingford anarchist that he was brought up to be, and briefly looked on course to make it through to the sort of mid-innings conditions that his game is more used to facing. But then, he slapped too widely at Kumara's heavier length, and slapped his bat even harder in frustration.
Lawrence's toils are a reminder that England are a long way from a finished product, as indeed were the late-afternoon struggles of a callow attack in which Chris Woakes' experience has never seemed a more precious resource. The likelihood is that England will receive another of their habitual hurry-ups on Monday morning, an experience to rank alongside Wellington and Lord's in 2023 for self-immolation.
But will they learn a thing from the experience? Well, yes and no. On the one hand, we know by now that they change their ways for no-one - at least, not in a public, self-effacing manner. But, have they learned that their punt on Smith - with his raw yet refined power, and his uncanny ability to accelerate out of a tailspin - is one of the best they've ever made? You bet they have.