Leo Cullen says Leinster must use La Rochelle's House of Pain to come back and claim that fifth European star.
The Blues were blown away in the second half at the Stade Marcel-Deflandre yesterday as the La Rochelle of Jono Gibbes and Ronan O'Gara won 32-23 in their first-ever Champions Cup semi-final appearance.
The victory, secured after Leinster led 13-12 at the break, sets up an all-French final against Toulouse - who do have the chance to become the first club to win the competition five times - at Twickenham on Saturday, May 21.
Since last lifting the trophy in 2018, Leinster have lost a final, a quarter-final and now a semi-final.
Asked if this deserved defeat makes it feel like that fifth star harder will be harder to achieve, head coach Cullen said: "Well, the first one was very hard to get. We'd to wait a long time for the first one.
"So, yeah, it's going to be fascinating to watch. Toulouse are going for their fifth against La Rochelle, it would have been great to be there at Twickenham with some supporters.
"It's always a challenge, that's the amazing thing about the tournament.
"People expect that you're going to roll up and it'll happen for you, but you get a sense of the atmosphere in the town and how much it means to people here.
"That's great, that was us at one point in time trying to go for our first win.
"We'll keep battling away, working on our game and make sure we're better - bring some more guys through and give them an understanding of what's involved.
"When you go through some of the pain, you get the experience of what it's like.
"It's making sure when we get this opportunity again, we're better. We need to be better and get better."
Cullen pointed to the passion of the La Rochelle crowd that gathered outside the stadium for the arrival of the two teams as something that the younger members of his squad have to gain experience from.
"Particularly for the younger guys, I've sort of described that image as we pulled into the ground and you see that sea of supporters and what it means to the club and to the town here," he said.
"We need to understand that because we need to bottle up that kind of pain that certain people are feeling inside there.
"A huge amount of players experienced a semi-final in Europe for the first time so we just need to be better for the next opportunity or next window when we get to this stage of the competition because it's so hard winning away in France in a semi final, but it's something that we have done in the past.
"Everything's really deflated in there right now. "
