Leinster all set to secure quarter-final on home turf
This is at once a fixture that bookends European qualification and sees two teams whose beginnings were so uncertain but whose endings seem primed for a timely, finishing flourish.
For Leinster, restored to near full health, it seems they are akin to an iceberg, the tips of whose imposing potential supporters have rarely seen this season.
A losing bonus point defeat may be enough to see Wasps go through as one of three best runners-up but they'd be relying on Harlequins not collecting a five-point win against Castres to qualify for the last eight.
For Leinster, a home quarter-final which coach O'Connor has justifiably declared would be eminently winnable; like last season, an away tie would be naturally more awkward.
Just as Leinster's form has changed dramatically since day one, so too their task today against a markedly more resilient combination than the pitiful Castres side who waved the white towel in the RDS last weekend.
Worryingly for Ireland, less so for Leinster, Mike Ross remains out in the cold; instead Kane Douglas and Dominic Ryan, for Mike McCarthy and new Irish call-up Jack Conan, represent the only two changes to his side.
For Wasps, who also make only a brace of changes, James Gaskell is starting in the second row in place of Kearnan Myall, who picked up a bump last weekend but is fit to come off the bench.
Ben Jacobs starts in the centre alongside Elliot Daly, after the elusive Alapati Leiua injured his knee against Harlequins; pointedly, Dai Young has named two back-rowers on the bench, in anticipation for Leinster.
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"The thing that hurt Quins was the scoreboard," says O'Connor, following Conor O'Shea's early concession of a sloppy turnover try. "They went down on the scoreboard and they kept playing and they kept trying to score tries. We have looked at it very carefully this week.
"Thankfully, we were a little bit better in relation to our composure at the RDS when we went down and got a couple of scores and fought our way back.
"Our way is winning and that is what Saturday is about. We have to deliver a performance that leaves us in front after the 80 minutes." Leinster have enough key performers back hitting their groove, to ensure they can finish what they started today.
Leinster - R Kearney; McFadden, Fitzgerald, Madigan, D Kearney; Gopperth, Reddan; Bent, Cronin, Moore; Toner, Douglas; Ryan, Murphy, Heaslip capt. Reps: Strauss, Hagan, Furlong, McCarthy, Conan, Boss, G D'Arcy, Fanning. Wasps - R Miller; C Wade, E Daly, B Jacobs, T Varndell; A Goode, J Simpson; M Mullan,E Shervington, L Cittadini, B Davies, J Gaskell, A Johnson, J Haskell capt, Hughes. Reps: C Festuccia, S McIntyre, J Cooper-Woolley, Myall, G Thompson, E Jackson,A Lozowski, A Masi.
Ref - J Garces (France).
Leinster v Wasps
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