Ireland have tipped the Rugby World Cup upside down and set themselves on course for the most memorable campaign. They have done all of New Zealand a massive favour by beating the Wallabies and not just for the pure joy that brings in itself.
They have left Australia in grave danger now of having to meet South Africa in the quarter-finals. What they have also done is proven they are also genuine contenders. The Irish have come here to make amends for the horror campaign they endured in 2007. Job done on that front; now they can think seriously on how far they can push on. If they can repeat the intensity of last night - they are going to be dangerous.
When it comes to bravery and passion - no one does it better than the Irish. It's tempting to think it was their sheer energy and desire to be better than got them through. But that would be doing their forwards, particularly their hugely impressive loose trio, a massive disservice.
Plain and simple - Ireland were technically better at the business of hitting bodies out the way and clearing space.
Tactically they were smarter too - it has rained once or twice in Ireland and they knew how to play with a wet ball.
It was bump and burl from the forwards and Johnny Sexton sent it booming into night air when it came his way.
That's the simple version. There was more to it. The Irish forwards were low and hard in the drive and there was some neat, close-quarter offloading. They didn't just charge up the middle all wild-eyed and foaming mouthed.
There was control and enterprise about the way they moved the ball and then there was their defence. The men in green swarmed and hit; swarmed and hit. Quade Cooper had about as bad an evening as the last time he came to Eden Park and the Irish had obviously done their homework - realising that Will Genia and Cooper had to be contained.
Ireland's defence in the final minutes was thrilling. The Australians threw everything and the Irish held out - finally breaking free through Tommy Bowe who went inches from scoring at the other end.
What they also did was scrummage the confidence out of Australia.
When the Wallabies couldn't wriggle their way out of the engagement, they were toasted a few times at the scrum. They are masters at the art of avoidance; hopeless when it comes to a fair contest.
Ireland would have been keen to keep them in there for longer - to drain the Wallabies' legs of energy and to force the penalties. More importantly, it would have crushed the Wallabies psychologically. They still don't like being reminded of the fact they can't scrummage - well, not with the big boys anyway.
The Irish were also that bit stronger at the collisions. Pat McCabe made the repeat mistake of trying to bust holes from a seriously upright position. In he smashed and the Irish had no difficulty in keeping him off the ground.
Those little victories and a few others where the Irish were quicker and stronger over the tackled player were the component parts on which their confidence grew.
Each time the Irish regained the ball or sent the Wallabies reeling back, a little more belief flowed into the men in green.
They haven't always fulfilled their potential - certainly not at World Cups anyway - but this Irish team has men who regularly win big games. Leinster, who provided almost the half the squad, are the Heineken Cup holders and the toughest side in Europe. They know how to win under pressure - and what's more, they believe they can win under pressure.
Belief has been an old failing of Ireland's. The piece of the jigsaw they have been painfully been missing. They have it now.
Australia: 6 (J. O'Connor 2 pens)
Ireland: 15 (J. Sexton 2 pens, DG; R. O'Gara 2 pens)