Cullen's men could not be in a better place as their European journey begins
Champions Cup weeks always create a different kind of atmosphere in training from the word go on Monday morning.
This change of pace comes from the break in routine from what you were used to in the last eight weeks compared to the change of intensity that European rugby has traditionally required.
During a normal season this change of competition can clean the slate from a poor opening start to a season, or it can serve as a continuation of good form in a way of peaking at the right time.
For Leinster, on the eve of the Champions Cup, they could not be in a better position. Most people will compare them to this time last year, and rightly so as you are only as good as your last championship, but every season will have some woes in the lead-up to the European campaign.
It could be injury, form of the squad or it could be the form of the opposition's squad. Leinster could not be better placed to take on Castres at home tomorrow and expectation will be for a four-point dream start to the campaign.
The Munster game last weekend was looser than one would expect from the history of this fixture.
For the first 20 minutes, Leinster's composure and confidence in defence was enough to tire out a hard-working but rudderless Munster side.
Leinster did not need to show too much in attack, which was a testament to their strength and depth.
This will frustrate the Castres video analyst but he or she will learn that there is a potent attack force there when needed.
Luke McGrath must start the big games, and Rory O'Loughlin has impressed on his last two outings.
It is hard not to get excited about where the Johnny Sexton, Robbie Henshaw, Gary Ringrose axis is going to lead Leinster to.
There were glimpses of Rob Kearney and Isa Nacewa benefiting from being outside them, and there is much more to come from this backline.
Up front, the battle was at the usual high standard and as every Irish man will admit, both these sides need each other fighting like brothers, barring injury of course.
Leo Cullen's selection this week will be tough. Every player will want to start, especially with such a feelgood factor around.
With the talk of Sean O'Brien being back, it would be smart to give him a run, but with five other quality back-rows putting their hand up for selection, Leinster are in the enviable position of being able to select with a panoramic view over the next couple of games.
With a possible hint of Rhys Ruddock operating in the second-row, this would open up room in the back-row if needed to accommodate the rich supply.
When Munster did what they do best, they rolled over the Leinster line. Before this they were trying to get the ball wide and trying to expose space in the narrow defence but they did not succeed in getting the ball through the hands.
This is something Leinster might find other teams trying to do too.
If opposition teams get the ball wide or indeed kick to that space, Leinster will need to scramble in defence which will upset their current structure.
With Leinster's defence operating so well it gives their attack a somewhat relaxed edge. It is clear they are playing heads-up rugby where they are adjusting on the go to the immediate opposition weakness.
There was lots to smile about from last weekend and plenty of teeth shown by the Leinster management in the press conference afterwards.
Two out of two is a must against the French with a hope that by the time they meet again, they are out of Europe. Leinster need to manage their hard-earned resources over the next few weeks - and that includes the fans' natural increased levels of expectation.
There are bigger and tougher games ahead, but beating Munster will always heighten the spirits. Last season, the international window was a disruption; this time around it needs to be a mere inconvenience.