I believe we can win it again
O'Brien is ready for Europe and excited about the return of Sexton and Nacewa
Sean O'Brien has never been one to whisper in the dark.
The true Blue flanker's opinion, like Excalibur, is set in stone.
It will not be withdrawn unless Leinster run out of road in 'The Group of Death' for this Champions Cup.
"I believe we have what it takes to win Europe again," he said.
"There is an awful lot of work to go-in in the meantime.
"But, with the squad we have, we should be there or thereabouts."
This is a statement of honesty, not of an idle boast.
It is also the mindset of a man with a winning mentality that has been forged out of club and international evidence.
He is not alone. He just says it as he sees it. And as he plays it. Simple. Straight forward. Direct.
"There is no point in brushing over the fact that we want to go out and win Europe.
"We all do. It is as simple as that."
There are those in Toulon, Bath and even Wasps, who have the same concrete, bloody-minded opinion born out of recent or inherited history.
The French are looking for a mind-boggling fourth successive title, Bath (1998) their second, Wasps (2204 and 2007) a third. This makes it nine crowns shared among the four heads. There is no lack of belief at what can be done.
"Every other team is probably the same," he acknowledged.
"With the squad we have, we're well capable of doing that."
It is one matter to want something badly, quite another to have the embedded, unbending belief to make it happen.
The statistics are there as evidence of fact.
The Tullow man has three Heineken Cup medals in the Tank.
They were pocketed before the rise of 'the galacticos' of Toulon, who stand as a monument to the financial change in the game.
You see, money can buy you everything. Just not all of the time.
Stade Francais showed that in the French Championship last season. Leinster almost did in Europe.
As backs coach Girvan Dempsey put it so simply and so effectively, Leinster were "one foot away from the final" last season when Jimmy Gopperth's drop goal slid to the wrong side of the post against Toulon.
"I feel that we've a better squad this year and we've an improved set-up - new ideas."
The return of The Prodigal Sons, Jonathan Sexton and Isa Nacewa, the smartly chosen captain, adds world-class attitude, action and decision-makers.
"We're better placed with Johnny and Isa coming in," imparted the flanker.
The return to old ways has also refuelled the thirst to sup from more silverware with Dempsey being allowed to introduce the attacking philosophy practised in the British & Irish Cup during his apprenticeship there.
"There are some great ideas," touted O'Brien.
There have been other positives to draw on.
For the most part, the Ireland internationals at the World Cup have returned relatively unscathed.
The experienced All Black Maori Hayden Triggs already looks like a smart piece of business at second row.
The likes of backs Cathal Marsh and Garry Ringrose, hooker James Tracy, flankers Josh van der Flier and Dan Leavy, on limited game time, and second row Ross Molony have all looked the part in the PRO12.
The next generation stepped up in the first block of five matches in a way they weren't able to by the time the Six Nations window closed last season.
"It is an exciting time for Leinster. The young lads have done very well. They've stepped up to the mark.
Wasps will bring a better set of players than last year on Sunday.
For instance, James Haskell is fit again and the destructive Ashley Johnson has made the soul-searching move to hooker.
Then, there is the everlasting 35 year-old George Smith, the veteran of 111 caps for Australia
O'Brien makes no secret of the fact that he will probably go eyeball-on-eyeball with one of his childhood heroes.
"He was one of my favourite players growing up," he stated.
"You always look at the top internationals. He was one of them for many years."
The Wallaby centurion is still going strong at 35 and seems to be an international man of travel, having played in Japan, France, for three clubs, England and Australia.
The Irish flanker scoffs at any suggestion that Smith is living on his reputation.
"He has a great skills-set. He poaches. He's very smart. He carries. He can link. He has it all and he's shown that throughout his whole career."
"He is someone you would have a massive amount of respect for what he's done.
"He's still going strongly and has proven himself over and over again."
The same could be said for O'Brien.
"It is an exciting match to start it," admitted the Carlow man.
"There's no better place to start it than at home in the RDS. Hopefully, we can produce the gods and start on the front-foot and kick on from there."