The question as to whether it was a head-butt or drunken greeting was a point of fevered discussion which even elicited the question as to whether Bancroft would be good enough to grade it on a scale of 1-10 with one being an affectionate nuzzle and 10 being the full ‘Glasgow kiss’.
He declined to offer a mark for the record.
But behind the laughter and the jokes it was England not Australia who were feeling the effects of not one but two blows.
One, off the field, where they have been manoeuvred into a singularly uncomfortable position given they are already struggling to deal with the absence of Ben Stokes after another night out, and the other on it, where they lost the first Test in emphatic fashion.
It is no wonder Steve Smith could barely contain himself with laughter so much for him went right in Brisbane.
He scored 141 unbeaten runs, his side won by 10 wickets, his bowlers bounced out England like it was 2013 all over again, they sledged out Bairstow, and now England were having to deal with a PR crisis.
Yet there are reasons to believe England can wipe the smile from his face in Adelaide because this result, while one sided in numbers, was most certainly decided by very fine margins on the pitch.
Bairstow had issued a po-faced statement which did little to shine a light on what actually happened in The Avenue bar in Perth on October 29.
But Bancroft later revealed that he thought the England player “weird” but “not malicious”.
“He connected with my head,” said the opener, smiling as his captain Smith collapsed in fits of laughter beside him. “With a force that would make me think, ‘Wow, that’s a bit weird. I had been expecting a handshake or something’.
“But although it was the greeting I was expecting there was certainly no malice in his action and we continued on having a very good conversation for the rest of the evening.”
England are annoyed to have been suckered into this four weeks after the event and there is a feeling within the camp that the Australians, on learning of the incident (presumably when Bancroft was called up), have chosen to wait to use it to their advantage on their first day of dominance on day four at The Gabba.
Smith said: “I think it was basically about trying to get Jonny off his game, to be honest with you. And I think it worked with the way he got out, caught at third man playing a pretty ordinary stroke.
“We were just trying to get in his head, and it happened to work.”
The wider issue for England is whether Smith’s fast bowlers have got inside their heads after a predictably ferocious assault which swept away the tail and gave the main batters a difficult time including Root who was hit on the helmet.
“They exploited the conditions very well,” said the England captain. “It was difficult on a two paced wicket to know when to get under the ball. When it carries through if the bounce is true, it can be a lot easier to play some times.
“When it’s two paced, knowing when to stand up and play it can be quite challenging and we got that slightly wrong. But it would be easy to fall into a trap of thinking it’s a big problem.
“We have to believe and trust in the work that we have been doing and backing ourselves and each other as a group. A lot of the time we played strong cricket. Guys made good starts and everyone proved that they can cope with these conditions and their attack.
“It’s just doing it for longer periods of time. When guys do it going in and making big hundreds.”
Root was right to point out that England played some excellent cricket and got themselves into several strong positions in the match, notably at 246-4 in their first innings only to collapse to 302, when Australia were 76-4 and 209-7 only to let them get a first innings lead, then again in 155-5 in the second innings before crumbling to 195 all out.
Although they failed to convert those strong positions, there are reasons for optimism going to Adelaide this weekend with a pink ball day-night Test expected to provide the lateral movement England need to unsettle the Australian batsmen.
Hard wickets, fast and short bowling are right up their street but even the mighty Smith, will not be so comfortable if the swing of Jimmy Anderson under lights starts to move off a true line.
Root and co need to wipe the smile from Australian faces, knock the swagger from their stride and level the series in South Australia. They also do not need any more off field distractions for the remainder of the tour.