IT is squeaky bum time for Joe Schmidt and his cohorts.
"We need a number of results to go our way to get a four-point win and qualify," he said.
"We need Monptellier to lose by more than seven points. We need Toulouse to either win or lose by more than seven points and we need Munster to lose as well.
"I taught English not Maths, so it is beyond me. I want to keep it as simple as possible. We want to try to present as tough a task for other people to keep us out," he added.
In other words, Leinster will hunt the four tries, the five points, with every fibre of their being and every play in the book.
The cool of the Leinster coach's exterior must betray a kaleidoscope of emotions that turn the stomach as surely as milk is churned into butter.
He wouldn't have it any other way. The natural competitor within him thrives in a pressure cooker atmosphere. He knows the environment. It usually brings out the best in him.
Rob Baxter's Exeter Chiefs like to win ball, keep ball and play ball. The oval leather object is their friend and they always aim to use it with width.
"There is no one secret formula," said Schmidt, in relation to how to make a minor miracle happen.
"I know last time we played them we made over 160 tackles. They keep the ball for long periods. They put width in their game. They have a lot of structure to their game," said Schmidt.
The problem is that they are just as eager without the ball as they are with it. They don't mind the rough and tumble. That is what The Premiership is about, first and foremost.
"They reload and get back in positions really well. They are difficult to combat. They resource the rucks really well and they've got guys who are very efficient in there, the likes of (Tom) Johnson, (Richard) Baxter and (James) Scaysbrook.
"Dean Mumm has played a lot at loose forward as well as in the second row and Tom Hayes gets about for them," he added.
Exeter treasure the ball. They protect it at the breakdown in order to send their close-in runners around the corner with the ultimate aim of making the touchline their friend.
"For a team that plays with that much width, they can sometimes get exposed. But, they are very well organised and they anticipate play well.
"They have played a lot together. They came up through The Championship and into The Premiership. They really gel as a unit incredibly well."
The fact that the Devon club has not given up four tries to anyone, except Clermont-Auvergne, in 29 months speaks volumes for their motivation to work right to the end.
"You go into a game with a premier plan, a secondary plan and, maybe, and a tertiary plan. Depending on how the game starts off, you chase one of the three," stated Schmidt.
"You have a certain way that you feel you need to start the game and you take it from there."