The night of truth, in some respects. it's one thing cutting a swathe through your fellow Celts, quite another to topple the standard-bearers of French rugby. even by their own admission, Leinster haven't really been put under pressure yet this season, but they assuredly will be tonight.
After seven successive wins at Celtic level, to a degree too they've also been jolted a little by the events at Murrayfield last week, so both they and Irish rugby could do with an immediate pick-me-up.
Having strengthened their squad, avoided injuries and accumulated wins, Leinster have never looked better equipped to deliver.
This match should, of course, have taken place in Toulouse tomorrow, but Leinster rightly ceded to the French club's request that the match be switched to Dublin after the explosion at an Azf factory in toulouse a week ago which left 29 people dead, over 100 injured and damaged the roof of the Stade des Sept deniers.
Flags will be at half-mast inside the ground and there will be a minute's silence before the game, and many Toulouse officials and people alike have praised Leinster for their co-operation in the matter.
Stade Toulousain are, by some way, the biggest and most vibrant sports club in the southern French city and quite how this tragedy will affect their players one can only imagine. the French champions had begun the season sluggishly in any case, losing away to beziers and at home to Biarritz.
Bedevilled by injuries, they will be missing Stephane Ougier for the campaign, hitherto ever-present in their 39 cup games, and at the outset Emile Ntamack, Yann Delaigue and Cedric Soulette, while Cristian Califano has gone to auckland for a year.
Nevertheless, in a remarkable statement of their strength in depth, Toulouse still field 13 internationals in tonight's line-up (Leinster, by the by, field 11, and all of them Irish).
A crop of exciting backs are amongst their newcomers, who also include the stylish Pau acquisition David Aucagne. The new 20-year-old French full back, Nicolas Jeanjean, will be making his cup debut, as will 23-year-old Cedric Heymans alongside the relative veteran Michel Marfaing: the competition's record try-scorer with 20 tries in 32 appearances. "I expect them to be what they are," says Williams, "one of the best teams at this level in the world." Yet, watching some of the high-tempo skill levels Leinster have displayed this season, it's fair to say that their skill levels are right up there.
Now they're starting to acquire the experience, too; last season's loss of nerve against Edinburgh, which cost them a quarter-final, may yet be a catalyst for a turnaround as well.
True, the comparatively lightweight Celtic opposition so far will be chalk compared to French cheese, though Swansea did attempt to batter a second-string Leinster opposition into submission.
Powerful though the pack and the back row appear, there is a doubt within French circles as to whether they would have the desired speed and mobility in a fast, wide game.
Here Keith Gleeson, whose continuity skills have added another dimension to Leinster's game, could come into his own. Besides which they can roll up their sleeves if they have to, for the scrums and lineouts have become serious weapons this past year under Roly Meates and Willie Anderson.
A knock-on affect of this weekend's switch is that Leinster will, disconcertingly, play three home games in a row and finish with three away games. Two of their three games will be at Donnybrook rather than Lansdowne Road, where this game was to have been played next January, and Donnybrook diehards will be grateful for that.
Moving to Lansdowne may have swelled the branch's coffers, but was hardly inclined to boost Leinster's chances. Aside from being much more pleasant than the decrepit headquarters, this place has become a bit of a fortress in its own right, which is, dare one say it, almost Munsteresque.
After 13 games without losing at Donnybrook, something special is brewing at the venue.
Leinster: G Dempsey; D Hickie, B O'Driscoll, S Horgan, G D'arcy; N Spooner, B O'Meara; R Corrigan (capt), S Byrne, E Byrne, L Cullen, M O'Kelly, E Miller, V Costello, K Gleeson. Replacements: G Hickie, P Coyle, T Brennan, B Casey, B Willis, A Dunne, A Magro.
Toulouse: N Meanjean; C Heymans, C Desbrosse, X Garbajosa, M Marfaing; D Aucagne, J Fillol; A Lo Cicero, Y Bru, F Tournaire, H Miorin, F Pelous (capt), J Bouilhou, I Maka, C Labit. Replacements: W Servat, B Lecouls, F Belot, S Dispagne, J Cazalbou, F Michalak, F Maka.
Previous meetings: ('97-98) Leinster 25 Toulouse 34, Toulouse 38 Leinster 19.
Leading EC try scorers (95-01): Leinster - John McWeeney 8, Denis Hickie 6. Toulouse - Michael Marfaing 20, Emile Ntamack 19.
Leading EC points scorers (95-01): Leinster:Alan McGowan 225. Toulouse: Michel Marfaing 246.
Referee: S Lander (England).
Odds (Paddy Powers): 1/3 Leinster, 18/1 draw, 9/4 Toulouse. handicap odds (Toulouse +9pts), 10/11 Leinster, 16/1 draw, 10/11 Toulouse.
Forecast: Leinster to win.
