The All Blacks are going to find out a lot about themselves.
My view is that they will already have discovered those truths in the review of the second test and the build-up to this final test. You only had to see how impressive they were in defeat to realise that they will have looked in on themselves first and foremost to work out why they lost, rather than look out externally to find an excuse.
If you make excuses, you are giving yourself an out.
There will have been no fuss or anger. It will have been a factual, rather than emotional analysis, process-driven.
For me, the conclusion will have been that they were too conservative. They need to be bolder, more assured, playing the All Black way that we have come to know.
They over-kicked in Wellington. They played a territory-power game, rather than a territory-skill game.
Even though the conditions were atrocious, they should have backed themselves more with ball-in-hand, put people through holes.
All the attacking stats were in the Lions' favour. The All Blacks kicked 30% more than the Lions did.
The Lions made six line-breaks for one from the All Blacks, with five off-loads to three. That is a significant reversal of styles.
That is what the All Blacks will be attending to, not to any gripes on the night, even though I felt that they had the rough end of the refereeing. Not on the Sonny Bill Williams sending off, which was absolutely the right decision.
There was no point in saying that the French referee, Jerome Garces, was stricter than (South African) Jaco Peyper might have been. Any ref in the world would have sent off Sonny Bill.
For me, there was no malice in it, just very poor judgment.
The same was not true of the Mako Vunipola incident (clearing-out Beauden Barrett). Vunipola was fortunate that he did not get red.
But the final penalty, given against Charlie Faumuina, who tackled Kyle Sinckler when he was momentarily off the ground taking a pass, left me gob-smacked. I'd like to think that I have watched more games of rugby than most on the planet and I have never seen a penalty given for an offence like that.
By the very letter of the law, there might have been a bit of justification. But the law was never intended to cover such situations.
What next? Players jumping in the air all the time to avoid a tackle?
The All Blacks have got on with the job. There has been unfair criticism of Beauden Barrett in all this.
First of all, for his goal-kicking. It is worth pointing out that he did land seven, a record against a Lions team.
He did miss three, but I have no issues with him were he to continue the goal-kicking duties on Saturday, rather than it passing to his brother, Jordie.
The All Black selectors have been bold with the selection of both Jordie Barrett and Ngani Laumape, both starting in their first Tests. That¹s a big call in this must-win game.
As for Beauden's open-field play, he has been hampered somewhat by having to switch to full-back in the first test, when Ryan Crotty went off, and again with the injury to Waisake Naholo.
Beauden needs to stay true to himself and bold, and take the ball over the gain-line and then play the appropriate option, rather than always having 12 or the blind-side wing carrying into contact.
Taking the ball into contact just gives this wonderful Lions defence a second opportunity to regroup and defend off the breakdown, and this is an area that they are simply outstanding.
That we have reached this terrific climax is a great tribute to the Lions. Warren Gatland deserves great credit for bringing it all together.
There have been no sideshows, no distractions within camp. They have been as one.
It has amazed me how they have managed to do that, even though they have had to cope with an itinerary from hell. It would have been hard enough to keep your head above water, let alone be in this position.
That there has been no more verbal sparring between Steve (Hansen) and Warren shows how much respect is there.
And, yes, I agree with Steve Tew (CEO of the New Zealand union), that Warren should be a contender as next All Black coach. He has gone through the ropes, coped with all sorts of adversity in the ring, and come out strongly.
So, to the contest itself. It will not be about attitude - that is a given.
Both teams will be at the right pitch mentally. Technique, though, in all aspects will be paramount.
Take the breakdown. If the ball-carrier can stay up, rather than go to ground early, and then the cleaners win the height battle, entering low and driving past the ball, it will win that crucial phase.
It will be the same all over the field.
Of course, it will be a passionate experience for players, for coaches, for everyone at Eden Park. And, of course, there is pressure on the All Blacks.
There is every time they pull on the jersey. Kieran Read wins his 100th cap and has been a fine servant of New Zealand rugby.
But he will be focussing not on himself, or on the emotion of the day. He will be intent on doing his job.
We must all savour the occasion for what it is. We are talking a special moment, the biggest game in New Zealand since the 2011 Rugby World Cup final.
The All Blacks prevailed that day - just - and I believe they will again.
-Daily Telegraph