One of only four teams who have played in all 16 seasons of the Heineken Cup - Toulouse, Munster and Ulster and the others - Leinster will become the second Irish side to reach the 100 game landmark as they follow in the footsteps of Munster.
They will join Toulouse (112 before Friday night's clash with Glasgow Warriors) and Munster (111 before Sunday's game with the Ospreys) in ERC's Elite 100 club - although not before Leicester Tigers have pipped them to third place in Perpignan on Saturday afternoon.
The Tigers, the only club to achieve back-to-back Heineken Cup triumphs in 2001 and 2002 and five times finalists, will become the first English club to reach 100 games. They have also done so without having taken part in the inaugural tournament in 1995/96 and in 1998/99, when no English clubs took part.
One man bridges the gap from the Tigers' first and 100th game. Current Head Coach Richard Cockerill was in the middle of the front row at Lansdowne Road in 1996, has been a part of the club through their four finals and will be in charge of operations in Perpignan.
"I can still remember playing at Lansdowne Road. It was the start of a journey for the club in Europe and nobody knew how big the tournament was going to become," said Cockerill.
"It was a bit like going into the unknown in those early seasons. I had never heard of Pau before we went there, but it was great to experience the different mentality and cultures.
"The physicality of the French game was something we hadn't come across before. These days the unknown isn't really there because everyone does so much research into the opposition.
"The competition isn't better or worse now, it is just different - but equally as enjoyable. Everyone now sees it as the premier competition and if you want to be seen as the best of the best you have to win it.
"When we won the title back-to-back it was a special era for the club with a special group of players. In the modern game I don't think you could buy a squad as good as that and it is unlikely that sides' will have that dominance ever again.
"Everything was stacked against us in 2001 when we had to go to Paris to play Stade Francais Paris in the final. Everyone expected them to win, but the way the game swung, and the rugby we played to win, was as good as it gets.
"A year later against Munster in Cardiff everyone thought it was their turn to win it. But we were at our stubborn and belligerent best and won it again - that summed up the way we were at the time.
"It would be enormous for the club in the modern era, when the salary cap in England makes it difficult to compete financially with the French and Irish, to win the Heineken Cup again.
"It is the biggest competition domestically in the world and to win it just shows where you are in the game. All the players know that when it comes to playing in Europe, it's a big fixture that always has a special feel about it."
LEINSTER GAME 1 - Wednesday, 1 November, 1995 (K-O 2.30pm)
Milan 21, Leinster 24
Pool C, Round 1 - Stadio Comunale Giuriati, Milan
HT: 8-14 Att: 1,200
Milan: F Williams; R Crotti, M Platania, M Tomassi, M Cuttitta; D Dominguez, M Bonomi; S Cerioni, C Orlandi, F Properzi Curti, G Croci, F Berni, T Ciccio, D Beretta, G Milano (captain)
Replacement: M Giovanelli
Scorers: Tries: R Crotti, M Platania; Con: M Bonomi; Pens: D Dominguez 3
Leinster: C O'Shea; P Gavin, V Cunningham, K McQuilkin, N Woods; A McGowan, A Rolland; H Hurley, S Byrne, P Wallace, M O'Kelly, B Rigney, C Pim (captain), D Oswald, V Costello
Scorers: Tries: C O'Shea, N Woods; Con: A McGowan; Pens: A McGowan 4
Referee: Franck Maciello (France)
LEICESTER GAME 1 - Wednesday, 16 October, 1996 (K-O 6.45pm)
Leinster 10, Leicester 27
Pool B, Round 2 - Lansdowne Road, Dublin
HT: 10-13 Att: 3,500
Leinster: P McKenna; P Gavin, K McQuilkin, M Ridge, D O'Mahony; A McGowan, A Rolland; H Hurley, M McDermott, P Wallace, N Francis, M O'Kelly, C Pim (captain), V Costello, S Rooney
Replacements: C Clarke, R Governey.
Scorers: Try: Penalty Try; Con: A McGowan; Pen: A McGowan
Leicester: G Austin; S Hackney, S Potter, W Greenwood, L Lloyd; R Liley, A Kardooni; G Rowntree, R Cockerill, D Garforth, M Johnson (captain), M Poole, J Wells, E Miller, W Johnson
Replacement: N Malone
Scorers: Tries: G Rowntree, A Kardooni, J Wells; Cons: R Liley 3; Pens: R Liley 2
Referee: Joel Dume (France)