It’s not much more than two years since the province was anchored in the depths of self-doubt.
The barrel was scraped with defeat to Wasps in January of 2016 when they conceded 50-plus points in continental surrounds for the first time since the 1990s.
It didn’t matter that Leo Cullen had been thrown a hospital pass by the club the previous summer. Asked to assume the reigns after Matt O’Connor’s exit, the former captain had just a year as forwards coach under the Australian when he was handed the deeds.
Add in the disruption of a World Cup that denuded him of so many Ireland players and Cullen’s early days were spent dealing with a sinkhole rather than building solid foundations and yet it didn’t stop calls for his dismissal in the wake of their dismal Champions Cup campaign.
And now look at them. And him.
The raw materials were always there in Leinster but the ability of Cullen and his staff to meld them in such a way as to produce a performance like the one that accounted for Scarlets on Saturday should not be underestimated.
Cullen was big enough to accept that he needed help. Graham Henry was brought in to consult two summers ago and then Stuart Lancaster, a man used to calling the shots with England, was embraced under the vague but telling title of ‘senior coach’.
Lancaster’s role has been praised to the hilt by the players since and, if there is still some haziness as to who is responsible for what on the outside, and who is calling what shots, then there is more than enough clarity for those tasked with carrying out the instructions.
“He’s had a great impact from when he came back from Leicester as a player to captain us to three trophies and now leading the way at the top,” said Jonathan Sexton of Cullen. “The organisation relies on top down, the leadership from above.
“It was a big decision to bring in Stuart as well and share the workload. Stuart has been immense as well so big credit to all those coaches. This week especially has been brilliant and the preparation that went in has been outstanding.”
The proof of all that was clear to see two days ago.
Leinster destroyed a Scarlets side that had their number in last season’s Guinness PRO12 semi-final down the road in the RDS, obliterating them with a powerful, direct brand of rugby that contained just enough width and variation to keep the Welsh guessing.
First-half tries from James Ryan, Cian Healy and Fergus McFadden left it 24-9 to the Irish side at the interval and then Scott Fardy and Sexton had added a pair more before Tadhg Beirne managed a consolation for the Scarlets a minute from time.
It was brutal and effective and yet Cullen believes they can do better than this again.
“A couple of penalties that we gave away were probably in our control, which puts a bit more unnecessary pressure on ourselves. We gave up a try at the end. So, there were a few areas we could manage better. Overall, we are delighted with how the guys went.”
It’s not just the head coach who has had to learn on the hoof. Cullen delved into the changing landscape in the club game in recent years and how the club’s inability to live with the Toulons and Saracens of the new world order had forced a rethink. More than that: a reboot.
The next challenge for him and Leinster is navigating the path from here to the season’s end and finding the balance for players so that they are both sufficiently rested and sharp for the bigger games as both competitions come to a defining end.
“It’s just managing the demands of the season and understanding you’re going to be missing players at certain times of the year,” said Cullen.
“How we invest in the resources is a big thing. The work that we do, understanding how we manage a competitive group as well, so we can manage the whole squad.
“And that everyone understands the role they play in getting the team to some of these big days because it’s frustrating for some guys.
“A lot of guys have played a part in getting the team to this point in both competitions and sometimes they don’t get to play in some of these knockout games.”
A good headache, and one the Leinster brains trust look increasingly capable of dealing with.
R Kearney; F McFadden, G Ringrose, R Henshaw, I Nacewa; J Sexton, J Gibson-Park; C Healy, S Cronin, T Furlong; D Toner, J Ryan; S Fardy, D Leavy, J Murphy.
J Larmour for McFadden (HT); J McGrath for Healy (54); J Tracy for Cronin (58); A Porter for Furlong (61); J Carbery for Sexton (62); J Conan for Leavy (67); N McCarthy for Gibson-Park and R Molony for Ryan (both 71).
R Patchell; L Halfpenny, S Williams, H Parkes, S Evans; D Jones, G Davies; R Evans, K Owens, S Lee; T Beirne, D Bulbring; A Shingler, J Davies, J Barclay.
R Elias for Owens and W Kruger For Lee (both 53); L Rawlins for Bulbring (55); S Cummins for Shingler (67); A Davies for G Davies and W Boyde for Barclay (both 71); D Evans for Evans and S Hughes for Williams (both 75).
R Poite (France).