Painful Wasps' sting will serve as warning to watchful Leinster
The name of the game this week is all Leinster need to remain grounded.
Wasps in the Champions Cup. 33-6. Three years ago this Friday.
There's an attic full of memories right there. No need to unfurl the gamut of humility mottos, then.
It was Jonathan Sexton's first game back in Leinster blue after a Parisien sortie where he had failed to add to his three European titles.
But now this? As he surveyed the shattered dressing-room, the prospects of a fourth title a distant illusion, the prodigal son might have been forgiven for questioning his judgment.
"I'm sure he did," laughs Luke McGrath now, humour soothing the painful reminiscence.
"I've no doubt he did. It was just so quiet in the changing-room. It was bleak. Leo Cullen spoke about our standards.
"Whatever about losing on that score, just in the RDS where we have such a great home run at the moment... that was a very difficult thing to take."
International Rugby Newsletter
McGrath was a second-half sub that day, arriving just as his scrum-half rival Joe Simpson had put even more daylight on the scoreboard despite the gathering dusk.
Already 23-6 down, Leinster would cough up another 10. Small mercies. "Not too bad then," he grimaces, faintly smiling.
"I knew coming on I just have to speed up the ball somehow. But we were chasing the game from early on. I remember Christian Wade scored a turnover try from a mistake by us.
"They are just so lethal off turnover ball, you saw it in the Aviva in the quarter-final as well. But a lot has changed since then in both squads."
And for Leinster, particularly. They would lose another four European games after that; their final outing, beating Bath, could never be classed as a resurrection.
It did, though, mark the beginning of a collective rehabilitation.
Six players - Garry Ringrose, Luke McGrath, Peter Dooley, James Tracy, Tadhg Furlong and Ross Molony - would debut that day and begin the process of hauling Leinster back towards the summit of their once faltering ambition.
"It was an unbelievable amount of hard work that's gone in from everyone to get to here," says the Irish international.
"Winning another Champions Cup seemed miles away.
"We were probably cheating ourselves in a way, thinking, 'This is easy' when you're coming in but a lot of players have moved on and we definitely got humbled that year. Hopefully, it never happens again.
"Beating Bath was massive in giving us the belief to move on and improve and a lot of those lads were significant towards the end of last year.
"That game was incredible for us young lads but if you look at the bigger picture, that was the only game we won that year.
"It's important we keep those standards and don't go back to a place like that. They are not great memories. We have come on a lot since then.
"However, there was the fear there we mightn't be able to live up to the previous generations. But, then, Stuart Lancaster came in and a lot of young talent came through at the same time.
"We had a great mix last year between the young and more experienced guys that had done it.
"But they were very bleak memories back then. We just had to make sure that never happened again.
"It's important we know we have a target on our backs now because we are the champions. We need to keep those high standards and keep improving."
Individual responsibility will galvanise the collective push. McGrath was in his third full season then but only making his 34th season; the retirements of Eoin Reddan and Isaac Boss within weeks of each other would propel him to the forefront.
"It did seem like a long way for me but I knew at that stage I had a long way to go in my development.
"I knew I had to train hard each day, try to constantly learn off these guys and their experience, and put it to my advantage.
"The two of them retired at the same time and I knew there was a massive opportunity to take there. I've been trying to improve as a player every day since."
Leinster, who may only field three of the side who featured three weeks ago, may be without McGrath's rival for the nine shirt, Jamison Gibson-Park, who rolled an ankle in the weekend win against Munster and is unlikely to be risked.
That would allow Cullen to field the other two "foreign" players, Scott Fardy and the in-form James Lowe. Jordan Larmour will return to replace Fergus McFadden after shrugging off a hip problem.
Brad Shields, Lima Sopoaga and Willie le Roux return for Wasps, although Joe Launchbury may be lost to surgery.