Forty-five minutes before kick-off, Joe Schmidt and Gregor Townsend shot the breeze on the side of the pitch while their respective squads warmed up in intense humidity behind them. By their demeanour you could have mistaken this for a pre-season friendly.
Despite the outward calm, both coaches fully understood the significance of what was about to unfold over the next two hours. For the winner, not only the spoils, but control of Pool A with the potential to bypass New Zealand at the quarter-final stage.
After what we witnessed on Saturday night in that titanic Southern Hemisphere face-off with South Africa, avoiding the All Blacks offers the most promising route for a prolonged stay at this tournament. First things first however, and for Schmidt the only thing on his mind walking away from Townsend was beatingScotland.
The growing list of players visiting sick bay since Ireland’s arrival in Japan left Schmidt admitting in advance of this game to feelings of nervousness. After all he has invested in this squad over the last four years in the build up to this World Cup, who could blame him?
Not in his wildest dreams could he have envisaged what was about to unfold over the opening 16 minutes alone. Two trademark tries, engineered by taking ownership of the opposition 22 - two inspirational scores from James Ryan and Rory Best.
Both had their foundations in the set-piece, the scrum platform setting up the opening for the indefatigable Ryan to announce his arrival at his first World Cup, the lineout maul the launchpad for Best’s key effort. In the second quarter, Tadhg Furlong capped a wonderful period for the front five union by scoring Ireland’s third try.
How Best managed to hold onto the ball under immense pressure from Scottish No 8 Ryan Wilson, and in handling conditions that have made some of the best players in the game look silly over the opening three days of action, was some feat.
The most reassuring aspect of this quality performance was that it contained all the elements that made Ireland such a potent team in 2018. Set-piece solidity, breakdown mastery, an ability to retain possession over multiple phases, a rock solid defence and a kicking game that put the highly-rated Scottish back three in reverse all afternoon.
One has to factor in the fact that Scotland were woeful. This, after all, was the most experienced Scottish side ever, with a combined 630 caps. They fielded a back line with five British and Irish Lions and a back row that Townsend was confident would create havoc for Ireland at the breakdown.
In many respects, Scotland appeared guilty of believing their own hype. While Schmidt was admitting to anxiety, Townsend revealed that his squad had never trained better in the week leading up to this one.
Perhaps his players needed reassurance after losing six of their last seven games against Ireland. They just never seem to learn from the mistakes of the past. Townsend has instilled an all-out attacking mindset in this backline which, given the quality of proven runners such as Stuart Hogg is reasonable, but even New Zealand know that there is a time to kick and a time to run.
In their desire to capitalise on the space Ireland leave in the wide channels, Scotland passed latterly across the field in an effort to launch Hogg into that space. That played right into the hands of a voracious Irish defence that clearly absorbed all the lessons of that embarrassing showing in Twickenham last month.
Who knows just how significant that painful reversal may yet prove. How often do we hear coaches and players proclaim how much they learn in defeat. On that basis alone defence coach Andy Farrell has earned his corn.
Ireland’s midfield defence was voracious, with Bundee Aki and Garry Ringrose landing a few really telling hits on Scotland’s key playmaker Finn Russell early on. When Aki was forced off in the first half, Chris Farrell emerged off the bench and put in a massive shift on both sides of the ball. Some of his defensive hits were bone shaking while in attack his lines of running and sublime offloading created numerous opportunities for others.
When Tadhg Beirne was sin binned in the closing stages, Farrell finished his shift in the back row of the scrum along with Jack Conan and Niall Scannell. If Schmidt was told in advance that was going to be his finishing back row, he would have had palpitations.
By that stage, however, this game was long over as a contest. When Andrew Conway capped a very competent outing by scoring Ireland’s fourth try to bag a bonus point after only 56 minutes, this game was done and dusted.
The big unknown coming into this one was how the inexperienced back three, who had never played together before, of Conway, Jordon Larmour and Jacob Stockdale would cope. The absence of Rob Kearney and Keith Earls, who between them boasted more caps on 180 than the entire Irish bench with 101, offered Scotland a predictable early target.
Russell wasted no time in testing them out but the two early bombs that reined down on Larmour were not only dealt with confidently but afforded him the chance to show his attacking prowess. All three more that stood up to the test with Stockdale making far better reads in defense while displaying his customary brilliance in attack.
The kicking game unleashed by Johnny Sexton and Conor Murray was back to its best which enabled all the back three to contest in the air with their Scottish counterparts, one such effort leading to Conway’s try.
Once again Schmidt was spot on with his selections. Josh Van Der Flier had a monumental game, his work rate sublime. CJ Stander was also back to his influential best while Peter O Mahony was shaping up well before being forced off with a knock to the head. His replacement Conan made big claims for a starting position next time out leaving Schmidt with the type of headache all coaches prefer.
On top of that, all the experienced players looked more like their old selves. Best was outstanding and, incredibly for a 37-year-old in such demanding conditions, put in an 80-minute shift. Iain Henderson delivered the type of all-round performance he is capable of.
On this form, his second row partnership with Ryan offers real possibilities. Behind such a dominant platform, Sexton and Murray controlled proceedings from the outset, completely outplaying their highly-rated Scottish counterparts.
Right now Ireland are in a good place. The feeling in that Irish dressing room, after all the hard work they have put in since assembly back in June will now feel worth it. They have control of their own destiny and have bought time for the injured players to fight their way back into contention.
Schmidt has serious competition for starting places and different options open to him, depending on the opposition. In a tournament like a World Cup, momentum is everything.
Right now Ireland have that and Schmidt has the opportunity of mixing and matching his troops in order to get what he perceives to be his strongest starting side in as fresh a position as possible to cope with what, on the back of this weekend’s results, looks like the much predicted reunion with Rassie Erasmus, Felix Jones and their Springbok monsters.