It is the moment of truth for defending Heineken Cup champions Leinster when they clash with the Scarlets under the RDS floodlights on Saturday evening.
It is a contest the three-times champions of Europe simply have to win - and potentially win with a bonus point to boot - to stay in the mix for quarter-final qualification.
Back-to-back defeats by ASM Clermont Auvergne, the crack French club now eight points clear at the top, have left Leinster playing catch-up with more of the same of their Round 5 target needed in Round 6 on the road at Exeter Chiefs.
And Leinster back row forward Kevin McLaughlin admits the pressure is on to avoid failing to qualify for the knock-out stages for the first time since the 2007/08 tournament.
"There's an element of the season almost starting now or almost ending now," said McLaughlin. As a team we don't like the thought of being out of Europe in January - we kind of look at January as the make-or-break month for the team.
"Obviously, the Pro12 is starting to pick up now. But we're a team that has been at the top of Europe for the last few years and we want to stay there.
"We've put ourselves in this position now, so it's going to be very much a case that, hopefully, our season is starting. We desperately don't want it to end.
"But I don't think we've ever been in this tight a situation in my time in Leinster. There is definitely an element of extra pressure there, but I think our attack has definitely sharpened up a little bit. With the internationals back, I think we are functioning better.
"We are playing with more confidence and there's no reason why we can't score a few tries at the weekend."
