Pressure is often misunderstood. It's attributed with being a factor that can cause random reactions in big games when in fact its impact is mostly predictable.
Pressure doesn't bring the unexpected – it typically sees players and teams revert to certain traits and behaviours that are embedded deepest.
Far from becoming volatile and harder to read, teams are at their most predictable when they are riddled with doubts and anxiety.
The Irish, under pressure, try to carry the ball harder, tackle harder, niggle more and bully their way back into the game. They have a fighter's mentality not a strategists.
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It's what they know – put them under pressure and they will try to smash and intimidate their opposition, because presumably that's their comfort zone.
Japan's coach Jamie Joseph made the most astute observation about this after his team had beaten Ireland. He said that they knew if Ireland went behind they would respond physically.
Right on cue, the Irish, realising the game was slipping away from them when they fell 19-12 behind, fired up and ran the same doomed lines and tried to work the same unimaginative plays, but with the addition of a pressure-induced rage that hadn't previously been there.
They offered the same thing but delivered it angrier. Japan had planned for it, knew it would come and were ready to respond by playing yet faster and wider and stretch Ireland further. That was Japan's default mode of dealing with pressure and their natural comfort zone.
Just like Japan, the All Blacks know what they are going to get with Ireland, have done for the last few years and yet the last three times they have played, New Zealand have been the ones to struggle psychologically, seemingly caught out by what they were facing and confused about how to react.
This has been Ireland's big advantage in the last few years – they have got inside the All Blacks' heads and twisted their thinking.
Strangely, when the All Blacks have been under pressure against Ireland, they haven't necessarily reverted to type.
The All Blacks have their own default mode under pressure. They typically go back to what they know best which is to play fast and wide. To pass and catch and probe for space.
They don't tighten their vision but expand it when they feel they are losing control of a game and their natural comfort zone is high tempo, high skilled rugby where they have the confidence to throw the critical pass and trust their skillsets.
But in recent games against Ireland, they have lost sight of their true selves and become muddled to the extent they haven't been able to go back to what they do best and have indeed become random and erratic under pressure rather than predictable.
It started in Chicago 2016 when Ireland did exactly what they said would and ran straight, hit rucks, kicked high, chased well and tackled hard.
The All Blacks were insipid in response. Bullied out of the game physically, dominated at the collisions, outplayed in the air and mostly shell-shocked that Ireland had indeed delivered the basic gameplan they promised.
Ireland's win that day was their first in history against New Zealand, the first defeat the All Blacks had known under Kieran Read's captaincy and also brought their record of 18 consecutive test victories to an end.
What made life particularly interesting was that the two teams met again in Dublin two weeks later.
The All Blacks needed to respond and they needed to win. Ireland had out-muscled them in Chicago so the All Blacks, feeling the most intense pressure for the first time under Read, decided they needed to meet Ireland's fire and fury with their own and 80 minutes of carnage ensued at Aviva Stadium.
Under pressure, the All Blacks responded physically. Their tackling bordered on reckless at times. They pushed the boundaries at breakdowns and attempted to intimidate Ireland out of the contest.
They picked up two yellow cards in the process and were lucky one was not red as it was later deemed to have met the threshold by the judiciary.
The All Blacks won, but it was an ugly victory, built on blinkered aggression that was almost dangerously out of control and as hooker Dane Coles says: "It was the first time the All Blacks had ever lost to Ireland [two weeks previously] so there was plenty of hurt amongst the boys.
"But if we turn up with that sort of attitude, especially at this World Cup, the way things are being reffed..."
The All Blacks, under pressure, didn't trust the full range of their weaponry. They had spent 2016 sweeping all comers out of the way with a devastating, attacking brand of high-skilled rugby that saw them average almost six tries a game and when they encountered their first real adversity – felt pressure like they hadn't before – they ditched the craft and guile and came out angry.
Their safe place was their pass and catch, their offloads, their continuity, their desire to run when they saw space and trust they would exploit it.
But they didn't go there that day in Dublin and by trying to beat up Ireland, they soured the relationship somewhat as the Irish were bitter to the point of publicly claiming that 12 incidents had been referred to the citing commissioner and 11 of them had been committed by the All Blacks.
The Irish used their sense of aggrievement last year when they next met and played with an intensity that was impressive.
They didn't mix up their game – just did what they have always done, but with a venom and relentlessness, that again seemed to take the All Blacks by surprise.
They must have known it was coming and yet played like they didn't. When they did eventually resort to type and try to play with the ball, the Irish knew that's exactly what the All Blacks would do and made shutting them down look easy.
So here we are now at the World Cup, a quarter-final no less, where the pressure for both teams is enormous.
But the All Blacks may have made the big mental breakthrough that was required. They seem to have worked out that the best way to twist Ireland into knots is to do nothing more than play their natural game.
Their team selection alone alludes to it but so do all the comments by the players and the quiet confidence exuding from the camp.
That's what Ireland fear the most – an All Blacks side that under pressure reverts to trait, but with the confidence to trust itself to be appropriately physical and disciplined.
The All Blacks don't need to reinvent themselves to win this game. They don't need to respond to pressure by re-thinking who they are or how they should be playing.
Their natural game should be able to put all the pressure back on Ireland and if it does, the All Blacks can be certain about what they will be facing.