There's a long list of things the All Blacks need to do better in Dublin than they did in Chicago and yet it's maybe just the one thing they need to fix.
Be it their lineout woes, their indiscipline, their lack of dominance at the collision, their poor handling, erratic decision-making and needless errors, they can all be contributed to one core factor - the All Blacks had the wrong attitude in the USA. As in, they didn't have any.
Rather than thinking they played poorly, it's better to think of it as they just didn't play.
They were passive. They were reactive. They were sloppy and as Sam Cane said, there was a sense of disbelief when the players gathered earlier this week to review their work at Soldier Field.
"What sticks out about with this one [review], there was a bit of embarrassment from us when you see some of the footy," he said. "And you see that's not what we are about, that's pretty poor footy. There was certainly an uncomfortable feel in the room which was good."
Plenty of reasons have been put forward to explain why the All Blacks didn't have the sense of urgency and dynamism they needed. They had gone 18 tests without defeat and inevitably, some training and preparation standards had slipped. Not noticeably, but enough to have an impact.
Head coach Steve Hansen has wondered whether heads were in the right space after spending the day before the test as part of the Cubs' World Series celebrations.
It doesn't really matter now, as Hansen is confident that the loss has forced everything under the microscope and that if complacency had been in the system, it no longer is. If minds weren't quite on the job two weeks ago, they definitely are now.
"There is a lot of people who didn't play a couple of weeks ago and they will be disappointed by that," Hansen said. "They are highly competitive athletes so their motivation will be high. I don't think motivation will be a problem. Complacency certainly won't be a problem and attitudinally they are in the house.
"You have just got to go out and prepare the best you can and then go on to deliver a performance you can be proud of. If the opposition are better than you on the day then you have got to accept that.
"When you make 16 unforced errors out of 21 that is something you have to fix and 12 out of 12 penalties were avoidable. Twelve out of 12 you are on the money when you are having an off day. They want to kick to the corners and have driving mauls and I think they scored two tries off of that so you are giving them what they want and you have to try to avoid that.
"We don't have any God-given right to win every game of rugby but what we do know is that if we prepare well and our attitude is good then we are hard to beat. The other team has to do the same."
This isn't precisely how Hansen sees things, but it's a near enough summation to say that the specific technical faults will mostly be fixed by adopting a vastly improved, generic mind-set.
The All Blacks aren't suddenly riddled with faults because they didn't play well against Ireland. They didn't become technically incompetent or tactically inept.
The lineout had been superb all season and then had a 40-minute malfunction without Sam Whitelock and Brodie Retallick. The return of those two will go a long way to restoring order at both the set piece and collisions.
With better lineout ball will come the opportunity to launch more effective attacks. If there is sharper handling then it will allow the All Blacks to play in front of the gainline and then compound the misery by attacking with momentum off second phase.
Win the nasty stuff in the forwards and it creates time and space for the key decision-makers Aaron Smith and Beauden Barrett to wield their respective influence. It's not such a complicated business.
"If everyone does their core roles, whether it is the lineout, the breakdown, on attack or defence then that should fix the performance and take it to a far better level than it was," said Hansen. "Whether that is good enough, we will see on Saturday.
"We think he [Smith] is the best halfback in the world. You guys [Irish media] probably think Connor Murray is so that will be how the battle goes I suppose - who goes well enough up front.
"Halfbacks usually play well if the tight five do the job as do loose forwards for that matter. Both tight fives have to provide a platform for their halfbacks who then allow their five-eighths to control the game. In Chicago [Johnny] Sexton and Murray controlled the game because of the platform they had from up front.
"As long as I have been watching rugby - which is a long time - until the day I die, that won't change. Rugby is about winning the battle up front."