Luke Fitzgerald accepts that three-in-a-row chasing Toulon are one of the best teams in Champions Cup history but insists Leinster can dethrone the holders with "a really big performance".

The Irish province face the expensively assembled French side in the last four in Marseille on Sunday (3.15pm) looking to save their season after last week's defeat to the Dragons left their Pro12 play-off hopes hanging by a thread.

"It's a massive, massive game for us," Fitzgerald told RTÉ Sport. "The pedigree of the team we're playing, going for three in a row, speaks for itself in terms of the quality of the opposition.

"Given the way we've played, it's probably a really big task to try and turn that around and bring out the best performance of the season, which it's what we're going to need to beat these guys.

"At this stage of the competition, every team you face, it's going to be a massive battle. In saying that, they're probably right up there in terms of the best to play in the competition ever. 

"The pedigree of the team we're playing, going for three in a row, speaks for itself in terms of the quality of the opposition"

"We've been in that position before, going for three in a row, so there's an awful lot of pressure on them.

"We're probably going there with nothing to lose and yet everything to lose; we're looking a bit shady in the league in terms of getting into the final four, it looks it's going to be a big ask, so this is a massive match for us. But probably more of the pressure is on them."

Head coach Matt O'Connor has come in for some criticism due to Leinster's league struggles and Fitzgerald thinks the players have something to prove for both O'Connor and their supporters.

"Nothing bar performance matters once you get on the pitch but I do think we owe the guys behind the scenes and the supporters a really big performance," he said.

"Everyone will appreciate the level of the task at hand but I still feel like we owe the guys something and I'd love to be part of a team that turns things around. It would really change how our season has been viewed so far."

"I don't think any team in Europe would be going there as favourites but I don't think that matters to the squad.

"We've been through a lot together. There are an awful lot of guys who have won the competition a few times. 

"I know, for me, I won't be thinking about who's favourites and who's not. I'm just thinking about who I'm marking, what kind of gameplan they play, how I can help the team out. They're the things all the guys will be focused on and I think that's something you probably get from having learned how to win the competition."

"What's important is that we're calm and composed, while being unbelievably aggressive. Unless we dominate the collisions, there's no way we can win the game, but we have to be composed while doing that and that's a real challenge in big matches. Usually, the team that stays calm on the big occasion is the team that wins."

Fitzgerald also pointed to the loss of some big players through injury as a mitigating factor this season - players who have now returned to the starting line-up.

"People are forgetting, we've had a lot of injuries this year," said the Ireland winger. "Guys like Sean O'Brien, a big talisman for the squad, Rhys Ruddock, Cian Healy, Richardt Strauss, Fergus McFadden. We've been pretty unlucky in that respect.

"If we get all the big moments in the game right, I see no reason why we can't turn those opinions around."

"Going into the Bath game we probably had three proper training sessions, so that's why there's a level of frustration with the negative viewpoint from the media and the supporters. It's understandable. They don't know these things but that's the reason why. 

"It was very important for us to get that time on deck, and we've had it now so there are no excuses this weekend."

"With one big performance, if we get all the big moments in the game right, I see no reason why we can't turn those opinions around."

Follow a live blog on Toulon v Leinster on the RTÉ website and News Now App from 3pm, with commentary on RTÉ Radio 1 Extra.

For more listen to Game On, weeknights from 7pm on 2fm