Stuart Lancaster is warning his Leinster charges that they cannot look beyond Friday's Guinness PRO14 semi-final showdown with Munster.
If results go their way, the Aviva Stadium clash will be the first of four huge knockout matches for the Blues in successive weeks, but the ex-England supremo believes his team face a dangerous opponent who will throw everything at them.
Munster's season is over if they go down on Friday night and Lancaster believes that will focus their minds.
Recalling the semi-final loss to the Scarlets in 2017, he reminded his team what can happen when they take their eye off the ball.
"It's all on this week," Lancaster said.
"There's no doubt in my mind that if you start thinking too far ahead about finals or quarter-finals or semi-finals in Europe, then you're going to come unstuck this weekend against a team that's highly motivated, extremely well-coached, full of high-quality players who haven't got a European competition to worry about.
"This is their season, it's our season. You don't want to put all the work into a PRO14 season and then come unstuck in a semi-final by not preparing properly and giving it the credit it deserves.
"People have worked too hard for that so there's absolutely no doubt."
Leinster will make a call on the fitness of Tadhg Furlong, James Ryan and Dan Leavy after training tomorrow. Leavy (knee) and Ryan (shoulder) did the warm-up with the team ahead of Saturday's win over Ulster, while Furlong is nursing a back issue.
"It depends on whether we think they've done the work in the training sessions. Dan Leavy, for example, did a full week last week. Now he's been out longer than James Ryan, 18 months is a long time," Lancaster said.
"James Ryan did a full week last week as well and he was obviously in great form prior to lockdown, so he's played a lot more recently.
"But that's what it will come down to, those decisions, but equally you've got to remember that ... take back-row, for example, very good players miss out.
"If you went through the back-row options whether it's Josh Murphy, Rhys Ruddock, Caelan Doris, Jack Conan, Dan Leavy, Josh van der Flier, Will Connors, Scott Penny, there's a lot of options. They've got to earn the right to get in the team.
"We want to finalise it on Wednesday and someone like Tadhg, you want to give someone of that calibre as long as possible. He's not ruled out but we need to make the decision because if he's not available, then Michael Bent, and Andrew Porter's been excellent as a start and Michael Bent will be a great option off the bench."