There have been plenty of big rivalries throughout the 29 years of the Investec Champions Cup.
As four-time winners of the competition, Leinster have had their share of great battles with the traditional powers of Europe like Leicester Tigers and Toulouse, before the likes of Toulon and Saracens became their nemeses during the 2010s.
In the last four years, La Rochelle have muscled in on the action, and as they prepare for their latest set-to with the Irish province, the pair are locked in arguably the best rivalry this competition has seen.
It says a lot about the French side's ascent that they have played just four quarter-finals in the Champions Cup before today, and made it all the way to the decider three times. Leinster, meanwhile are preparing for their 19th appearance in the quarters.
Even without the garnish of Ronan O'Gara being the head coach of the French side, this is a rivalry that has grown organically on the pitch.
Five meetings in four years will do that, with their first three duels coming in a semi-final, final and final in consecutive seasons. The last team to beat Leinster in this competition, aside from La Rochelle, were Saracens way back in 2020.
"That's the beauty of the tournament. It’s what makes it so special, some of the rivalries that are there," said Leinster head coach Leo Cullen, as the sides prepare to lock horns once again.
"Rivalry is the thing. It's great and we’re delighted to be part of the rivalry because we’ve to fight to make sure that we are there."
This year's Champions Cup has struggled to ignite, with a pool stage lacking jeopardy leading to a fairly predictable Round of 16 last week.
This evening's game at the Aviva Stadium (5.30pm, live on RTÉ) shows that when the conditions are right though, this competition can still captivate.
By Friday evening, there were just a handful of tickets left to shift, and those are likely to be snapped up by this afternoon, with a full-house of 51,700 expected at Lansdowne Road.
The product has always been good on the pitch when these sides meet, but in the last two years in particular, it's arguably been even better off it.
With O'Gara as head coach, and Donnacha Ryan and Sean Dougall on the backroom team, there's a distinct Munster flavour to La Rochelle.
Having won two Champions Cups and taken his team to two other Top14 finals in recent seasons, O'Gara probably stands alongside Rassie Erasmus as the game's most magnetic coach.
Every move, big or small, is viewed by their devotees as yet another masterful gambit, and all part of the grand plan.
In fairness, the La Rochelle coach has owned the occasion in each of those 2022 and 2023 final appearances, laying on the charm for the TV cameras and the media, and heaping pressure onto Leinster.
For the latest edition, O'Gara (below) and his side appear to have tapped into the old phrase: 'The enemy of my enemy is my friend'.
Having returned from an arduous last-16 trip to Cape Town, the French side moved straight on to Cork on Monday, spending the week leading up to this meeting with Leinster in the heart of Munster rugby.
"There seems to be a bit of a Cork bandwagon. The mafia have jumped onto the bandwagon along with La Rochelle," Cullen laughed.
"It's great, isn’t it? That’s what sport needs, doesn’t it, and I’m glad that we’re a part of it.
"For us, we're the only Irish team in the competition and you’d love if all of Ireland got behind you. But that’s not the way it works, as we know.
"But we’re the last man standing of the Irish provinces. The Bulls and ourselves are the last two teams from the URC in the competition. So we’re representing the competition that we play in.
"But again, that’s the beauty for sport here. Our guys are out there trying to fight the fight for Irish provincial rugby at the top table so to speak, but it’s tough work. It’s tough work to get there in the first place and then it’s about performing.
"Our guys are desperate to be successful, which brings a certain pressure but it’s a positive pressure because again it comes back to the crowd. They’re the ones that make the occasion in many ways."
While La Rochelle came out on top in the three knockout meetings between the pair, Leinster edged the defending champions 16-9 in their pool meeting back in France in December.
Both teams are missing key players from that day, with Garry Ringrose and James Ryan absent for Leinster, although they have been able to add in James Lowe and Tadhg Furlong.
La Rochelle, meanwhile, are without powerful front-rowers Reda Wardi, Pierre Bourgarit and Georges-Henri Colombes, not to mention full-back Brice Dulin.
"A lot of our lads have tonnes of experience," Cullen added.
"You've lost two very tight games against a good team, so you're still playing against a good team that still looks like they're desperate to go three in a row in the tournament, which, again, would be an amazing feat.
"For our guys, it's different. That's maybe their pressure, their expectation, or whatever it is. For us, it's a game in the Aviva, in front of friends and family and all the people that support the team. That's a different type of pressure.
"We've put the plans in place and we have two groups of players that are highly motivated. Then it's on the day, two good teams going at it.
"You've a winner and a loser and everyone will have their own opinion going into the game and, off the back of watching the game, people's opinions tend to change with the benefit of hindsight, and what they've seen.
"That's the beauty of sport because there are the unknown parts. Nobody knows exactly what's going to happen. But that's the beauty of what we're doing. It's exciting."
Listen to the RTÉ Rugby podcast on Apple Podcasts, Spotify or wherever you get your podcasts.
Watch Leinster v La Rochelle in the Investec Champions Cup quarter-finals on Saturday from 5pm on RTÉ2 and RTÉ Player.
Listen to live commentary Leinster v La Rochelle and Ireland v Wales in the Guinness Women's Six Nations from on RTÉ Radio 1's Saturday Sport, and follow live blogs of both on rte.ie/sport and the RTÉ News app.
