Munster captain Tadhg Beirne said the squad always retained the belief they could turn over La Rochelle after securing their first knockout Champions Cup win in three years.
Three tries from Craig Casey, Gavin Coombes and Andrew Smith, and a cleverly taken late drop-goal from Jack Crowley saw Munster heave themselves over the line for a one-point win over Ronan O'Gara's two-time champions, who were unable to rustle up the winning score in a tense endgame on the west coast of France.
The victory was redolent of Munster's glory days in the competition in the 2000s and sends them into a quarter-final, where the winners of Bordeaux and Ulster await. It is the province's first Champions Cup knockout win since they overcame Exeter in 2022 and their first on the road since beating Edinburgh in 2019.
"(It's) just phenomenal," Beirne told Premier Sports afterwards. "The feeling among the group, the belief going into this week.
"We were underdogs. But we always knew there was a bit more in us. There always is in this competition.
"You see the travelling support. We're in an away game, it's probably two to one. To have that many Munster fans come out to support us, it just brings our energy up and we're able to put in a performance like that.
"We knew there'd be a bit of a storm. They came at us and were probably unlucky not to have two tries at the start with the foot in touch.
"But we weathered that and came back into it. We controlled the second part of the first half. We came into the second half ready for another battle. It ebbed and flowed but we stuck in there. They gave it everything at the end but thankfully we were able to hold on."
La Rochelle's 65th-minute penalty try brought it back to a one score game but out-half Crowley - in an echo of the opposing coach - intervened with a smartly taken drop-goal, which made it a two-score game at a vital stage.
"You see it in training all the time," Beirne said of Crowley's composure. "You see how much he grows each week. It's a testament to his character.
"I seen him hitting a few in the warm-up. And I actually thought to myself, it'd be nice if he got one of them. And he got the exact one I seen him hit.
"What a kick, what a drop-goal that was. But the performance overall from him was incredible today, I thought he managed the game unbelievably well."
Munster's reward is a first quarter-final since their agonising loss to Toulouse after a penalty shootout in 2022.
They have to wait for outcome of tomorrow's Bordeaux-Ulster game to know the precise identity of their opponents. A shock Ulster win would give them a home tie in Thomond but the form-book points to a Bordeaux victory and another daunting trip to the west coast of France, where another Munster man - Noel McNamara - is part of the home team coaching set-up.
"We could be at home in Thomond but we could be away to Bordeaux," Beirne said. "Each of those are going to be tough.
"Another away trip over to France would be a difficult one. You see what we could produce here but we'd have to go up another level."
For Craig Casey, who darted over for Munster's opening try to level the game in the first half, it was a win which evoked memories of his childhood days watching the team.
"Growing up, you're watching Munster in Europe on special days and you want to be part of that," Casey told Premier Sports.
"Today was one of those days. It will go down in history in Munster folklore.
"It doesn't end here now. This isn't our Champions Cup final, we want to go further. It's all about next week, we'll recover. But what a day. We can't thank the travelling fans enough."
The scrum-half's try was created by a spectacular break from Thaakir Abrahams, with Casey remaining up the field in anticipation so he could be on the South African's shoulder.
"I was running in quicksand near the end," Casey said. "I was going 'oh my God, if I get caught here, so embarrassing!'
"The celebration was for Shane Daly, before anyone asks. He's one of the injured crew. He dared me to do it if we scored so nice one for him."
