The clenched teeth and pumped fists barely lasted an instant, concealed in a split-second gap for privacy in front of thousands before Ollie Robinson invaded his personal space with a bear hug. A look to the heavens followed, cheeks puffed, before the helmet went back on. He wasn't looking for anyone in particular up there, though of course he was grateful for any intervention from above. It was merely a chance to exhale all the stress into the atmosphere, and expel a few demons too.
It feels like a contradiction to describe a seventh century in the space of 18 months, and a 30th across a celebrated career, as "necessary". But Joe Root's reactions after nudging his 145th delivery of the day into the leg side suggest that the man himself might have believed it to be true.
An unwanted streak had been broken. A first three-figure score against Australia since Trent Bridge in 2015, finally closing a sequence of 12 half-centuries in 16 matches in the interim. As a heritage batter in an England Test team that had flunked all too often in that time, and as captain for most of those games too, perhaps Root himself had framed that period as a dereliction of duty. On the opening day of this series at Edgbaston, he went some way towards making amends.
This was as much a reiteration of his brilliance - a fifth consecutive fifty-plus score, a feat he achieved on one previous occasion when he managed six in 2014 and 2015 - as a clear indicator of his top-rank among high-flying renegades.
England's innings jagged chaotically like an MC Escher painting. The stairs were leading somewhere, but not all were going up. A fair few fell off altogether in their rush.
No dramas, of course. England's set-up is all about ensuring mistakes are made in the right way. This was just falling with style. But when 175 for 3 became 176 for 5 as Ben Stokes blazed the best-looking edge through to the wicketkeeper you ever did see, it did feel a bit much. And when the England captain's next act was to call an end to the innings on 393 for 8, it felt just fine.
Root's sensibilities became an even greater virtue. The process of rebuilding the innings was diligent, particularly in a stand with Jonny Bairstow which came to an end on 121 from 140. Moeen Ali button-bashed, Stuart Broad pressed the wrong button altogether, and Robinson, eventually, opted to stick around. By then, Root's status as the only adult in the room had been established.
Except, well, to describe this knock as "mature" might give you the wrong impression. Because while it was crafted by a seasoned hand, none of the pitfalls associated with maturity - limited creativity, suffocating responsibility - were on view. He was also charging up and down those upside-down stairs, albeit while remembering to keep one hand on the bannister.
The reverse-lap-scoop-jaw-dropper sweep, now as reliable a club in his bag as that dab that accesses the same part of third man (albeit on the ground rather than over), got two airings - first off Scott Boland, then Pat Cummins. Both went for six.
In the 50th over, as Nathan Lyon threatened to get into a groove, Root unfurled three successive reverse-sweeps. The first beat Josh Hazlewood's attempt in the deep to stop it from going for four. The second was scuffed off his glove onto his pad, meaning the lbw decision given against him was overturned on review. And yep, the third - more ramp than scoop, but very much from the same family, under the same roof - was nailed as an act of uncharacteristically showy defiance.
"It takes a lot of skill, a lot of endeavour and patience," Bairstow said afterwards, and he knows a lot about defiance.
"The way he manipulated the strike, the tempo of going up and down, sucking up pressure to then put pressure back on the opposition, is a trait of his that a lot of people would like to have."
We've always known that Root could be one of the boys if he wanted to, particularly given all this is very ODI Root. But it took time for the man himself to work out just how he wanted to fit in in his post-captaincy era. And having overcome a period of unnecessary introspection during the second half of 2022, this was the clearest indication yet that his decision to assume a more outlandish streak has enhanced previous strengths rather than drowned them out.
This is especially evident when you delve into the minutiae of this overdue Australian century. Coming into this Test, Root had hit five sixes against Australia. Two of them came in the 2013 home series, three in 2015. As captain in Ashes series - 29 innings across 15 matches - he did hit none. Today, he struck four.
The last, skipping down to Lyon and depositing him over his head, was the most manufactured of them all, after news of the impending declaration had been passed on covertly. That jaws were still slack with surprise at the move meant Root's ovation from the crowd was muted. But after taking a break for a rub-down as Australia's innings began, he returned for the field for the final over of the day to lead England off on one of its most storied days.
There's another important nugget here. England have not lost to Australia in matches where Root has scored centuries. Given the hosts' decision to advance the game, that already feels like a statistical quirk with less relevance. The game is still the same, but how it is being approached makes cues from history harder to gauge.
Not unlike Root. He remains very much the same, certainly in the eyes of his teammates.
"You see the smile on his face, you see the cheeky little grin that he has and when his legs bop around and runs through and what have you," Bairstow said, recalling the moment Root reached three figures. Somehow he was still reminiscing about previous days, even while discussing this one.
The Root of the past was great. The Root to come could be greater.