Though Bairstow made his return to the Test team against Ireland at Lord's earlier this month, his innings on Friday was his first visit to the crease for England since breaking his leg in a freak golfing accident in September last year.
He arrived at a critical juncture too, with England wobbling on 176 for 5 following the dismissal of Ben Stokes. However, he instigated another wave of attack in a 121-run partnership with his fellow Yorkshireman, Joe Root, and by the time he was stumped off Nathan Lyon, he had shown more than just a glimpse of his stellar form from 2022 than had made his recall non-negotiable.
"It was great fun being back out there, to be honest," Bairstow told Sky Sports. "It took a little bit of time to just get my rhythm, just to get my hands and my feet going. But I think when you come in off a lay-off like I have, that's going to take a bit of time. But when you're ready, you try and give it your best shot and, if it's there to hit, you try and give it a whack."
"Giving it a whack" was very much the order of another extraordinary day of England's new-look Test approach. The tone was set by Zak Crawley's blazing drive for four off Pat Cummins' first ball of the series, and continued at such a chaotic rate that Stokes was able declare the innings at 393 for 8 after 78 overs, leaving Australia four overs to survive before the close.
"Over the last 12 months, I don't think that's a change to what it's been like, to be honest with you," Bairstow said. "If the ball has been there to hit, the lads have tried to hit it. Sometimes you nick it, sometimes you miss it, sometimes you middle there. It's part and parcel of the game that we're fortunate to play.
"The intent that the lads showed - from, obviously, Zak's shot first ball of the day … I just heard it. I was like, wow, it's like a cannon … it's a stark contrast to when we were Down Under the last time.
"So it's been a good day. The crowd's been amazing, the lads have been on good form, really enjoying it, and that's exactly what we spoke about leading into the game.
"The lads are out there with a smile on their face," he added. "You can see that at the start of the day, whether it's in the warm-ups, or that first ball, and right to the end.
"International cricket is completely different to county cricket, and the occasion and everything is what we live for. And when your beans are going and your hands are going, that's exactly what I love. That's what it's all about."
England's typically high tempo of 5.03 runs per over meant that, for the fourth time in his captaincy, Stokes was able to declare England's first innings inside 100 overs. However, with Root unbeaten on 118 and looking good for several more on a true wicket, it was arguably the most contentious closure yet. Bairstow, however, insisted the faith that this team has in each other's roles means that they are confident that the bowlers will get stuck in on day two.
"It was a bold call, it was a good call," Bairstow said. "There will be conversations around it, but no-one likes going out there with 20 minutes and four overs, when you've got Stuart Broad and Ollie Robinson running in at the end of a day that has been a bit of a toil.
"The biggest thing is being patient and relentless on a length," he added. "They're going hit the middle of the bat because they're good players. But we're able to build pressure through our fields, through the ruthless lengths that we're able to hold, with the three guys [Broad, Robinson and James Anderson] that have got such a wealth of experience behind them.
"Whether the pitch is flat, whether it's swinging, whether it's seaming, I've no doubt that the guys will be able to call upon all those experiences, and all those times that it has potentially been flat. We will turn up in the morning and we'll see again. They had to start tonight, and they've got to start again, and it does take a couple of balls to get in."
With 11 wins in their last 13 Tests, however, England are riding a rare high in Test cricket, and Bairstow admitted that the confidence that that breeds could be critical for the rest of the contest.
"There's different pressures, but when you go in on the back of wins, and of people in some form, there's a huge amount of trust within each other to go out and do their own jobs individually, which then collectively comes together as a unit.
"Throughout the whole last 12 months, that's exactly what it's been about. It's about trust in each individual to go out and play their individual way."
Such are the reasons why Moeen Ali was tempted back to Test cricket after an absence of 21 months. His first innings back was a predictably hard-swinging knock of 18 from 17 with two fours and a big six down the ground. And, on a dry pitch that has already earned Lyon four first-innings wickets, his most important role could yet be to come.
"That's the brilliant thing about Mo," Bairstow said. "He comes in with that freedom and the thought process of, right, let's go and try and change the game. Let's go and try and win a game.
"That's the whole ethos of this team. How can we have those individual performances that enable you to go and win games? Not just go and compete, but go and actually take the game on, in order to put you and the team into a position that you can potentially force a result."
Andrew Miller is UK editor of ESPNcricinfo. @miller_cricket