Sexton ready for a show of force
Blues have to be at their best to have any chance
Toulon now hold the fear factor Leinster once used to their advantage in Europe.
The French kingpins will be aching from the feeling of whiplash they felt at the hands of Wasps two weeks ago.
They have since handed out wincing humiliations to Clemont-Auvergne at Stade Michelin and Agen at home in the French Top-14.
They will do all they can to avoid being where Leinster find themselves, two rounds in, two losses down.
"We've got nothing to lose," said Jonathan Sexton.
"We'll have to make our decisions early in the week. We've got to go over there and attack them and go at them - go for it - because we know there's no next week if we don't do that."
For all the world-class players on their roster, Toulon have the undeniable power of the 16th man - the Stade Felix Mayol.
"It will either inspire you or it will make you crumble," said the Ireland fly-half Sexton.
"It is an amazing place to play. The atmosphere is probably the best club ground you could go to."
The Ireland out-half knows all about the claustrophobic atmosphere from his two-year stint at Racing Metro.
"They are a very different team when you play them in their own stadium," he warned.
"These are the games that, I suppose, the players join Toulon for, these big European games.
"We're going to meet them at full force. It's a big challenge, but it's one that guys will hopefully step up to.
"We've got to either step up to it or we're going to be out of this tournament."
The merits of Toulon are long and almost unmatchable.
"They're not three times in a row European cup champions for nothing.
"They're outstanding. We're going to have to be on top of our game to be in with a shout."
Nonetheless, Sexton won't overlook Leinster's prolific feeder system into Ireland and how it might have an impact on matters.
"Look, we've got a lot of internationals that have played against these guys in their different countries," he added.
"They all come together in Toulon. Are they stronger than anyone of those other nations? I'm not sure.
"We can take great confidence that the guts of this Leinster team have beaten South Africa, have beaten Australia, have come close to beating the All Blacks.
"I suppose we can take confidence from that, that we have made up a large part of the Irish team over the last few years.
"We just need to find that something that's going to click us into gear."
The complete no show against Wasps was succeeded by a show of character without the points to match it at Bath.
Sexton charted an upward curve of performance from Wasps to Bath and on to Ulster in the PRO12 League.
"Hopefully, we're still building," he offered.
"Getting your set-piece right and taking your chances will probably be the two things we need to concentrate on this week."
The cancellation of the PRO12 match against Glasgow came at just the wrong time for a province in sight of that one 80-minute output they can draw on as a point of reference for the rest of the season.
"I'm quite confident with the group of players that we have.
"We are where we are. We just have to look at it that if we win the next four games (in Europe) we've a chance of going through."
It will take a miracle for Leinster to make it back from here.
Don't expect one.