Glory days on French soil give us belief – Jennings
If the old aristocrats are facing off at Thomond Park for the first time on Saturday, the new money meet by the Cote d'Azur a day later.
Toulouse and Munster are European royalty who played a major role in making this competition what it is today, but over the past few years the balance of power has moved away from them.
Taking their place are Toulon and Leinster, who have won four of the last five Heineken Cups between them and are currently in possession of the two European trophies.
That Toulouse won the 2010 installment cannot be overlooked and they beat Leinster along the way to that triumph, but the Blues avenged that defeat in the subsequent season's semi-final and Guy Noves' team have failed to get past the quarter-final stage in the two campaigns since.
Munster, meanwhile, saw their dominant era ended by Leinster in 2009, but it was the 2011 defeat to Toulon that truly signalled the final throes of that great team and almost forced Ronan O'Gara into retirement.
While both of the old guard remain threats for the title, as Munster's run to last year's semi-finals proved, the bookies view them as outsiders.
The two teams that meet – for the first time ever – on Sunday are placed second and third on the list of favourites behind Clermont Auvergne.
Sky Sports have been running ads based around the 'pilou pilou' chant with which Toulon fans will welcome Leinster and referee Wayne Barnes to their citadel, and it makes for intimidating stuff.
Leinster are buoyed by the fact that they have won in France already this year and have done battle against Clermont and Toulouse in their backyards in the past.
"It allows you to have a bit of belief whereas before you might doubt yourself," Shane Jennings said of the collective impact of winning three European Cups in five years.
"Every other team in the competition has the goal that they want to win it. Of course, they want to get to the quarter-finals, semi-finals, but it is about how you can be controlled in the game, to control those emotions, and then just be accurate and go through the patterns we're trying to set in place this week.
"You've got to bring a physical edge as well. There are a lot of things involved in it. But it is the process that you have to make sure you're doing right if you want to compete against these boys."
The main reference point Jennings drew upon was that 2010 semi-final defeat to Toulouse that ended Leinster's first title defence.
The openside, who was outstanding against Munster on Saturday, is one of nine starters who survive from that day, when Michael Cheika was forced to do without Johnny Sexton and the Blues' scrum folded at the Stade Municipal.
"Toulouse had a very strong pack, big men, very physical in defence, good line-out and scrum; this is what these guys have," he recalled.
"Like we experienced in Toulouse, Toulon have a dangerous backline. That day Toulouse didn't want to use it, they got their points out of penalties in the scrums and things like that. These guys are very dangerous, they scored a lot of points at the weekend (against Toulouse) and over the last number of years, they have been there or thereabouts in the Top 14.
"You don't do that by not being a good attacking team as well as a good defensive team. I heard Birch (Bernard Jackman, on the back-room staff at Grenoble) say that their defence was the best in France. It's a tight pitch, so it is going to be very difficult."
Part of the problem with Toulon is trying to second-guess who Bernard Laporte is going to pick given the quality available, but there is a steeliness about Leinster's approach this week, if their openside is anything to go by.
"Generally, we have a fair idea of what their tight-five is going to be. I'm pretty sure Juan Smith will play as well. They've just got such class players," he said.
"There is a massive element of 'we can't control that' so we will most certainly look after what we can do, recover well, prepare well and actually enjoy the week.
"We've been here before. We've enjoyed those weeks when there are big games. It is a great week for the club. We want to have another one of these. We all know you enjoy it when you're winning. We understand the stakes."