First-half shock, second-half awe ...
The events that unfolded before a disbelieving 72,000 supporters on Saturday evening defied the boundaries of logic and human exertion. This was an extraordinary game of rugby and you have to go back 12 years to find a reference point.
That leads you to the 1999 World Cup semi-final in Twickenham when France, emasculated by the All Blacks and referee Jim Fleming in the first half, roared back in the second to effect one of the greatest turnarounds in rugby history. This ranks right alongside and, arguably, above those Gallic heroics as Leinster took just 16 minutes to overhaul their 22-6 half-time deficit with an irresistible brand of multi-faceted attacking that rendered their brave, battered opponents powerless and scoreless, and could have culminated in an even greater margin of victory.
The implications of this astonishing performance carry great significance for Ireland's assault on the World Cup later this year -- a provincial template to steer national aspirations.
On the assumption that this was being beamed into the living room of Robbie Deans as he seeks critical information ahead of September's defining pool clash with Declan Kidney's side, it is safe to surmise that the Wallaby coach was squirming uncomfortably on his couch by the final whistle.
Ireland do not have Richardt Strauss, yet, but Leinster-bound Sean Cronin is cut from the same cloth. They do not have Nathan Hines, but Paul O'Connell carries the same power, and if Rob Kearney returns in full fettle, full-back Isa Nacewa has shown the way for his Leinster colleague.
But, aside from the individuals involved, if the collective sense of self-belief can be transfused into the Ireland bloodstream, the results could be equally spectacular. In particular, Deans will pore over the performance of Jonathan Sexton whose two-try, 28-point tour de force represents the greatest individual display in Heineken Cup history -- particularly when it emerged that it was the out-half who provided the primary words of inspiration at half-time.
And they were direly needed, for Leinster were not themselves in the first 40. Calm authority in defence has been one of the squad's core elements under Joe Schmidt, but time and again Northampton broke the line, usually on the inside shoulder, and, unbelievably, for a side defined by their parsimony this season, Leinster coughed up three tries.
With Steven Myler kicking with his customary efficiency and generally running matters from the platform of forward superiority, it looked like game over for the Irishmen who appeared to be riddled with doubt and uncertainty.
This started at the scrum, of which there were many, where Leinster conceded three penalties as the much-heralded Northampton front-row put the squeeze on. In this they were aided considerably by Romain Poite's leniency when it came to the bind but, even allowing for that, the Saints simply looked to have too much power and scores arrived as a direct consequence.
The first try from Phil Dowson came from an attacking scrum brought about by Sexton's enormous clearing kick crossing the dead ball line and Ben Foden's (Northampton's best player) second came when Leinster were shunted off their own ball by seven-man Saints who had young Tom Mercey on for the yellow-carded Brian Mujati.
Dylan Hartley's muscular effort just before the break also stemmed from solid scrum ball, and it truly was crisis time for the out-of-sorts favourites. All the basics of Leinster's game were below par, from Nathan Hines spilling a kick-off, to forced offloads and an inability to hold onto the ball.
The transformation was stunning. Scrum coach Greg Feek provided the technicalities that saw Mike Ross and Cian Healy suddenly establish scrum dominance (reinforced by Heinke van der Merwe's excellent contribution off the bench), and Sexton the inspiration.
Now running onto quick ball, the out-half used his pace and power to blast over for his two scores, and backed it up with points off the tee. The Leinster supporters, cowed by their first-half inferiority, played their part -- urged on by Sexton -- and when Ross and Co won a penalty for the lead after 55 minutes, with Luke Fitzgerald and Shane Horgan coming off their touchline stations to roar their approval, you knew there was only going to be one winner.
Hines and Gordon D'Arcy put their early woes behind them and the second-row touched down after 64 minutes, backing up more adrenalin-driven surging from Richardt Strauss and Sean O'Brien as well as a superb gather by Leo Cullen. Then there was Brian O'Driscoll. A doubt going into the game, the Ireland captain had struggled along with the rest of his team-mates in the first half, brilliantly mowed down by Foden when he did not quite have the gas to finish off his break for the line and being caught in defence on a few occasions.
However, in the second 40, O'Driscoll was immense -- one scoop off the ground at full tilt was a thing of exquisite beauty and the injury-doubt was still going strong at the end, executing a sublime behind-the-back pass as Leinster pushed for an end-game try.
Superiority off the bench was also a factor. Jim Mallinder emptied his in a desperate bid to stem the tide, but the Saints simply did not have the firepower in reserve to compete with the quality of Shane Jennings, Van der Merwe, Isaac Boss and Fergus McFadden.
The knock-on effects of this achievement will be far-reaching. In purely financial terms, although the prize money goes to the IRFU, the Leinster budget should be bolstered, while winning clauses in their various sponsorship deals will swell their coffers also.
In addition, the nature of this performance is guaranteed to increase the flow of youngsters into Leinster rugby, each yearning to be the next Sexton, O'Driscoll, O'Brien or, hopefully, Ross. With new state-of-the-art premises to be inhabited in Clonskeagh, a flourishing Academy, productive marketing and commercial operations and a growing support base, it is onwards and upwards for Leinster rugby -- who are now lining up an unprecedented double when they take on Munster in the Magners League Grand Final next weekend. The trick now is to bring that to bear on the national side and Ireland can approach the World Cup as genuine contenders.
That would have sounded outlandish three months ago, but a Leinster victory appeared equally surreal after 40 minutes of this remarkable affair. Leinster have proven that, with the right mix of belief and skill, anything is possible.
LEINSTER -- I Nacewa; S Horgan, B O'Driscoll, G D' Arcy (F McFadden 67), L Fitzgerald; J Sexton (I Madigan 76), E Reddan (I Boss 70); C Healy (H van der Merwe 60), R Strauss (J Harris-Wright 76), M Ross (S Wright 76), L Cullen (capt), N Hines (D Toner 76), K McLaughlin (S Jennings 40), S O'Brien (K McLaughlin 44-46), J Heaslip.
NORTHAMPTON SAINTS -- B Foden; C Ashton (S Commins 77), J Clarke, J Downey, P Diggin; S Myler (S Geraghty 66), L Dickson; S Tonga'uiha, D Hartley (capt, B Sharman 68) , B Mujati ( T Mercey 66), C Lawes, C Day (M Sorensen 76), C Clark (T Mercey 27-36), P Dowson, R Wilson (M Easter 62).
REF -- R Poite (France).