Cullen calls for patience as he looks to get campaign off to winning start
Leo Cullen is well aware of Wasps' European pedigree having been on the end of some of the English club's biggest victories during their glory days.
The Leinster coach was on the pitch when Warren Gatland's side beat his Leicester Tigers team in the 2007 Heineken Cup final, the last time the trophy was won by a team from across the Irish Sea.
After eight years of Irish and French dominance of Europe's elite competition, there is a real sense that the Premiership clubs are on the move once again and, with Wasps and Bath first up for the three-time champions in their opening two weeks, Leinster have a battle on their hands to stay alive in the tournament's most difficult pool.
Last season, Leinster opened their campaign against Wasps and had to come from 12 points down at the RDS to win. When the sides met again in Coventry, it was the English side who came from behind to gain a draw.
Bath, the team they narrowly beat in the quarter-final, lie in wait next week and Cullen knows that there is little room for error as champions Toulon lie in wait after that encounter.
Both teams have strengthened since last season's pool meetings, with Leinster adding Johnny Sexton and Isa Nacewa and Wasps bringing in Charles Piutau, Frank Halai and George Smith.
Whether that tips the balance in the English side's favour remains to be seen, but they certainly won't be underestimated this week.
Perhaps Cullen's biggest challenge as the coach of the bulk-suppliers to Ireland during the World Cup is re-integrating his internationals.
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Every one of his starting pack spent time with Ireland at the World Cup, while Noel Reid, Fergus McFadden and captain Nacewa are the only members of his side not to have played at the tournament.
Cullen brought his team to Wicklow for two nights this week to try and expedite that process and he is hoping that they click on opening day.
"We had 20 guys come back into the system two weeks ago, so there are a lot of combinations that aren't going to be perfect," he said.
"So we hope we will get improvements as the tournament goes on because we have worked closely with some and not with others because of the World Cup.
"There has to be a certain sense of reality as well.
"We are building in a certain direction and it is almost like when everyone comes back in you have to take a good few steps back to the foundation level so you can start building again and that can be frustrating."
That exit will have played on the players' minds too. It is less than a month since their disappointing defeat to Argentina and there is a mental challenge involved in picking his players up.
"Some guys hadn't played so much during the World Cup and were trying to get back up to speed and we were trying to get them minutes under their belts, that's another challenge," he said.
"Other guys were very heavily involved but they just needed time away to clear their heads and come back in.
"We want to create an environment where they are excited to come in because everyone wants to get back on the horse and be a really good rugby player again.
"It's important that we can change that focus, for the most part guys have shown a real enthusiasm to get back playing again. It's still early days in the season even though there's been such a build-up to the World Cup, there's nobody who's played a huge amount of minutes so far."
Getting over the gainline could prove to be a difficulty for the three-time champions after Ben Te'o failed to recover from his glute injury in time to take his place, while Luke Fitzgerald and Rob Kearney are also absent behind the scrum.
That means a relatively unproven centre partnership of Reid and McFadden line up outside Sexton and Eoin Reddan, with Nacewa, Zane Kirchner and Dave Kearney in the back three.
They, perhaps, have the toughest challenge with Wasps possessing a major threat in the wide channels where pacy pair Christian Wade and Frank Halai will combine with Ulster-bound All Black Charles Piutau.
They are missing players, with Leonardo Ghiraldini and Jimmy Gopperth suspended and captain James Haskell injured but still possess plenty of quality and could hold the edge in the second-row where Joe Launchbury and Bradley Davies are quality operators.
Much will depend on the battle of the back-rows where Australian openside Smith will be closely watched by Sean O'Brien, while Nathan Hughes' ball-carrying abilities must be watched by the Leinster defenders who must stop him getting up a head of steam.
If the Premiership team can get over the gainline and break tackles, then they have the playmaking abilities of Elliott Daly to create for their potent outside backs and can cause the hosts real problems.
But, with Sexton back in harness and a pack full of internationals with something to prove, the Irish province have plenty of threats of their own.
Games like this are the reason they were so desperate for their out-half to come home and now is his time to deliver. If the pack can get the upper hand, then Sexton should have the platform to win it.
LEINSTER -- I Nacewa (capt); Z Kirchner, F McFadden, N Reid, D Kearney; J Sexton, E Reddan; J McGrath, R Strauss, M Ross; D Toner, M McCarthy; J Murphy, S O'Brien, J Heaslip. Reps: S Cronin, C Healy, T Furlong, H Triggs, J Conan, L McGrath, I Madigan, G Ringrose.
Wasps -- C Piutau; C Wade, E Daly, B Jacobs, F Halai; R Jackson, J Simpson; M Mullan (c), C Festuccia, J Cooper-Woolley; J Launchbury, B Davies; S Jones, G Smith, N Hughes. Reps: A Johnson, S McIntyre, P Swainston, J Gaskell, G Thompson, D Robson, A Lozowski, S Tagicakibau.
Referee: M Raynal (France)
Leinster v Wasps, live, BT Sport Europe, tomorrow, 1.0