Ireland ready to take on world after setting new standard
Even Joe Schmidt admitted that he is "intimidated" by following 2017-18.
Coming on the back of a November clean sweep and a third Grand Slam, this series win in Australia rubber-stamped Ireland's status as World Cup contenders.
Off-field controversy means nobody could reflect on this as a 'perfect' season for Irish rugby, but while the IRFU have work to do on the game's reputation, the performance side of the house are delivering in spades.
Just 15 months out from the big kick-off in Japan, this June was crucial for assessing the runners and riders for the Webb Ellis trophy and, while Ireland stood tall, there is reason to suspect they are not the only ones getting their house in order.
Nine matches remain for Schmidt between now and the first warm-up game and, while a busy November will necessitate squad rotation, there is a sense that he is close to handing out all the new caps he is going to before next summer's tournament.
After Saturday's win, there was a notable name-check for Ulster's utility back Will Addison, who trained with the squad in Melbourne and may yet enter the equation, but after making James Ryan, Dan Leavy, Andrew Porter, Jacob Stockdale and Jordan Larmour key parts of his matchday 23, it is time now to build experience and grow belief.
In time, and without the shadow of a World Cup, the magnitude of this season will be fully appreciated, but even the way Schmidt picked his teams for this successful jaunt Down Under showed just how much everything is being framed through the prism of Japan.
The experience of being a long way from home for a substantial period while playing high-class opposition will stand to the team, as will the latest taste of that winning feeling.
They are not bulletproof, but this team are difficult to beat, yet they also have a capacity to make their wins less comfortable.
Even when they struggled in Brisbane they had enough chances to win the game, but they should never have been defending a one-score lead at the death in Melbourne and might have got further ahead in Sydney with a tad more composure.
The grand finale of a superb series was a tough game to digest given the influence of the officials and the see-saw nature of the play, and a tiring Ireland side showed character to guts it out.
Their fitness has been supreme all season and their ability to manage players and avoid injury is the envy of their rivals.
Conor Murray, Johnny Sexton, Robbie Henshaw, Jack McGrath, Tadhg Furlong, Peter O'Mahony and CJ Stander were on last summer's Lions tour, but a year later they were starting and winning.
They can happily bask in the glory of it all for the next few weeks, but when they gather in a Carton House room in August, Schmidt will challenge them to take another step up.
Whether they can do it or not will determine whether the World Cup quarter-final glass ceiling can be broken. If it is, then anything is possible.
What this series showed was that even at the end of such a superb series, Ireland cannot expect to beat members of the Rugby Championship away from Dublin without a struggle.
England will bounce back, France are on the up and South Africa are showing signs of life. Argentina and Scotland are enigmatic, but Wales are building again. New Zealand remain a class apart.
After such success it is easy to wonder how Ireland can go even higher in terms of performance, but there is scope to improve.
Once they get through a few phases, their attacking game remains somewhat one-dimensional, and it becomes difficult to power over the best defences - especially as fatigue sets in.
With Garry Ringrose in the team, Ireland look a far more exciting prospect, but the physical capacities of Bundee Aki and Robbie Henshaw are difficult to ignore. Finding the right balance in midfield is key.
There will be some concern about how the set-piece creaked against the Wallabies and, with Greg Feek now working remotely from Japan, the scope to improve the scrum might be limited.
And, while there is now depth in most positions, there is still significant risk if they lose either Murray or Sexton.
Joey Carbery did well in the series opener, but there was still a noticeable improvement when Sexton came in. Ireland are praying he will hit the ground running at Munster.
Despite not coming on in Sydney, Ross Byrne will have gained valuable experience in training, while there is strong talk of an Irish-qualified No.10 arriving in Ulster to bolster the options.
Still, Sexton is so, so important, and if anything happened to him it would be disastrous.
At least Carbery got some much-needed experience on tour, whereas Kieran Marmion and John Cooney were limited to brief cameos off the bench.
Schmidt neatly side-stepped a question about his scrum-half depth last week, but he must be aware of the risk he is taking.
Luke McGrath remains the most like-for-like replacement for Murray, but he was left at home and is already back in pre-season with Leinster.
While Marmion has credit from the 2017 Six Nations, it is not enough for him to get a start, and Cooney saw a frantic few minutes at the unfamiliar position of out-half in game two.
Only the heat of battle will prove whether a player can handle a World Cup, and we are no wiser with regards to what would happen if Murray went down.
He has made progress in defining the pecking order at hooker where Sean Cronin has lost huge ground, while the return of Rhys Ruddock, Josh van der Flier and Sean O'Brien means back-row is an area of real strength.
Ireland are in arguably their strongest position and, while there are a number of risks, they are primed for a serious assault on the World Cup.
Before that, they must reflect on a most successful season. It won't be forgotten.