This is the point the team have been waiting for for a long time. It's the last pool game and Ireland want to be in a quarter-final. They know exactly what they have to do.
A lot of the pressure is on Scotland, given that not only have they to win, they have to score four tries and then beat Ireland by at least eight points. So from that point of view, Scotland have it all to do. We know exactly how they are going to play, so it's going to be fascinating game.
If you look at the two teams, Scotland's strength is behind the scrum; that's where all their gold dust is. Everything will evolve around Finn Russell. The question mark is on the capacity of their forwards to deal with Ireland's physicality and on the quality of their front five.
Ireland have stood up to the best teams in the world over the last 18 months and if you look at their bench they would seem to have a lot more options there. Therefore, I'm not surprised that Scotland have gone with a 6:2 [split on the bench, six forwards], but I'm not sure whether it's going to work.
I look at the Irish bench, Dan Sheehan back in the starting team is huge; Rónan Kelleher has proved himself over a long period; Finlay Bealham has been a massive back up to Tadhg Furlong and now you have James Ryan on the bench.
That's three quality players that you can bring in to your front five - 25 minutes, a half an hour to go. The fact that Iain Henderson starts sends a message to everyone in the squad. He did brilliantly when he came off the bench against South Africa. James Ryan wasn't able to train fully this week, so the mantra with Andy Farrell has always been 'next man up'.
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That's the way it is. Even on the bench with Robbie Henshaw out, Stuart McCloskey, who has played no game in the World Cup, Andy Farrell turned to him and said 'this is your moment'. And that is why Ireland have been so impressive over the last two years: the next man stands up and they do a job.
I think Ireland have invested too much over the last two years to get to this point to let it fall. They know Scotland. We've won eight in a row, that is well documented. That run is going to fall at some stage but I think it would be catastrophic if they were to lose on this occasion.
Everything they've done has been geared towards this. I think overall, up front and behind the scrum, with Conor Murray to come in in the last 20 minutes, Ireland have the edge both in experience and in tactical nous.
Everything is about the next match and I was listening to something Martin Johnson said recently about the World Cup in 2003 - 'you can't win it until you're in the final'. That's exactly what Ireland need to take on board.
It's a huge game this week and a huge game the following week if they get through and that's what they have prepared for for a long time now.
You're in the business end of the World Cup now and you have to perform.
Donal Lenihan was speaking on RTÉ Radio 1's Morning Ireland.
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