Composure in midst of deep gloom. As with the latter months of his captaincy, so too with his new beginnings back in the ranks.
Lesser players might have drawn back the curtains in north London on Sunday morning, and baulked at the sight of Lord's enveloped in a thick blanket of cloud - never mizzly enough to prevent play from beginning on time, but seemingly perfectly weighted to the needs of New Zealand's seamers, as they resumed a dicey contest needing five more wickets before England could tick off their 61 remaining runs.
Joe Root, however, is nobody's idea of a lesser player. With a sense of purpose that might have been grafted from one of his very best white-ball tempo-setters, but in an occasion that dripped with Test cricket's full pomp and circumstance, Root got busy from the get-go, and New Zealand's challenge died a death by 10,000 cuts.
His first delivery of the day was dinked off the pads behind square - the purity of his angles against an arrow-straight sighter from Tim Southee rendering the stroke as riskless as a dead-batted prod back down the pitch. And if New Zealand didn't know it for certain at that moment, then that sinking feeling cannot have taken long to manifest. Thirty-four of Root's runs, but a solitary boundary, came from that soul-sapping nurdle, the most productive stroke of his innings - nay, his career - and on his watch something uncannily similar to calm descended over a restless, undulating match.
For in a contest that seemed destined to be defined by haymakers - "if they throw us two punches, we'll throw them four", as Matt Potts, England's debutant, evocatively put it on day one - it proved to be the deft caresses of Root and Ben Foakes that hurt New Zealand the most.
Had Kane Williamson been allowed to choose the manner in which England went about their victory push, he would surely have traded a few swings for the stands for the high probability of a crucial miscalibration - such as that which tipped Ben Stokes from the contest on the third afternoon. And in fact that would have been the plan had a wicket fallen on this final day. Stuart Broad was padded up and ready to go loco at No. 8, the logic being that his madcap methods were better unleashed with wickets in hand rather than at the very last ditch.
Root, however, specialises in a more passive brand of aggression. From the moment of Stokes' departure in the 50th over of the chase, he chipped off his last 81 runs from exactly 81 balls, a startling speed from a man who - aside from a handful of under-edged cuts in the final surge - never once looked rushed in the course of a 170-ball stay.
It was a point that Stokes acknowledged afterwards, as he harked back to the wisdom of the last England coach to attempt a fusion cuisine between England's red- and white-ball mindsets.
"As Trevor Bayliss used to say, it's not all about hitting fours and sixes," Stokes said. "You can be positive about the way that you leave, positive in the way you defend. It just makes things a lot easier, your decision-making, when you're looking to be proactive and positive."
Root's haste was such that, in sealing the contest inside the day's first 15 overs, he even secured a full refund for a gleefully receptive crowd - quite the populist's coup after all the pre-match discussion about ticket prices. Either way, he clearly wasn't the only national grandee laying on a free party this weekend - and as the players' kids took advantage of the early finish to turn cartwheels on the outfield while the Platinum Jubilee parade played out on the big screens above them, his glory put the seal on a nationally uplifting four-day weekend.
And in the midst of it all, lest we forget, he happened to tick off that 10,000-run mark. How often is it that the quest for landmarks becomes the story, over and above the reason why such landmarks are so sought-after in the first place?
For Root, who by a quirk of fate had begun this innings needing exactly 100 runs for five figures, the achievement came packed as if in the bowels of a Russian doll; a milestone within a century, within a run-chase, within the context of a team that had not tasted victory for ten month, within the broader - and soul-baringly-expressed - emotions of his first Test back in the ranks, having freed himself from an "unhealthy relationship" with the captaincy.
And once you'd unpacked all those layers, it wasn't hard to accept Root's assertion that, all other things considered, he really hadn't given the achievement a second thought.
"I'd been made aware of it, but after the shot I played in the first innings, it felt a long way off," Root said, recalling the critical stab to gully off Colin de Grandhomme that had set England's first-day collapse into full motion. "Winning was all I could think about. You pride yourself on winning, and it's been a long while for this team. It meant a huge amount to get over the line.
"It was very special to get the hundred and reach 10,000 runs, I can't pretend it wasn't, but nothing replicates winning games of cricket. It's such a good feeling and one I hope we can replicate through the rest of the summer."
Modesty aside, however, it is a startlingly vast landmark - a pinnacle that seemed so otherworldly back in the late 1980s when Sunil Gavaskar stood there alone, and still remains snow-capped with just 13 fellow greats having since traipsed their way to the top.
And while it's a common theme for England's record-setting batters in particular to reach such peaks with career records a notch below the highest standards - a reflection both of the number of Tests they get to play compared to their contemporaries, and the difficulties that English conditions can sometimes serve up - there are few criteria by which Root truly pales against his peers.
Yes, he is currently one of the few 10kers to average below 50, but he has the time and, clearly, the form to remedy that, while his failure to record that maiden century in Australia clearly hurts - mostly, of course, because Root himself knew that his own runs were the team's only realistic hope on either of his tours as captain.
But the true measure of Root's achievement will only be known in retrospect, because the history of the era that he is playing through - the pandemic on the one hand, and the real-time disintegration of the Test team that he has so proudly shorn up on the other - has not yet been written. Everything he is doing - for England in the first instance and for his legacy thereafter - is just too up-close-and-personal for a fair appraisal, but the manner in which Root has turned on the afterburners, almost from the moment of his 30th birthday in December 2020, has been legacy-defining.
In the space of 17 months, 2192 runs including nine hundreds have tripped off his bat - nine more, in fact, than his most fabled contemporaries, Virat Kohli, Steve Smith and Kane Williamson combined. Which goes to show, not that he's suddenly roared into a different league, but that a fluidity exists even in the mightiest careers, and that the very best recognise their moments and seize them with an alacrity that leaves merer mortals astounded.
Most extraordinarily, Root has achieved all this in a side that has just won its second Test in 18, and in which his 30 fellow players have scored five hundreds between them, with no other top-order batter averaging more than 31. Even Allan Border in his darkest days in the mid-1980s had a better support cast than that; even Andy Flower, in his gravity-defying era for Zimbabwe in 2000-01, had his brother Grant to hold up an end.
In time, the granular details of Root's batting achievements will begin to hold a greater sway in the imagination, even if for now, all we can do is laud the landmarks as they come. But take it as read that, when his team-mates spilled out of the dressing-room to envelop him in the Long Room during his victory march back through the pavilion, it wasn't just Root's runs they were celebrating, but the man himself.