Leo Cullen recalled the events of 2013 in the wake of Leinster's demolition of Northampton Saints in Franklin's Gardens.
Chris Boyd's team currently sit on top of the Gallagher Premiership, impressing observers with an attacking style of rugby.
However, they were humbled by a rampant Leinster in Saturday's Champions Cup Pool 1 game. The visitors only led by three points at half-time, but tore away from the hosts in the second half, racking up seven tries en route to a handsome win.
They sit top of the pool on 14 points heading into next weekend's return tie against the same opposition in the Aviva Stadium.
All would appear serene but speaking after the game, the head coach alluded to the shock defeat to Jim Mallinder's Northampton side in similar circumstances six years ago.
Matt O'Connor's Leinster battered Northampton 40-7 in Franklin's Gardens that season, Luke Fitzgerald running in a hat-trick and Brian O'Driscoll tossing exuberant under-the-legs passes.
Seven days later, however, they were stunned 18-9 in Dublin, George North and James Elliott notching the game's only two tries.
"We've been in this situation before where we've had a big win in Northampton and gone back to the Aviva been beaten," Cullen said afterwards.
"You've to be so careful with these fixtures. Normally, it's just onto the next team. It's a unique thing that takes place in the season where there's head-to-head fixtures. It doesn't always transfer into the following week.
"We've seen that first-hand ourselves in this exact fixture where we've had a win - similar to what we had today - and then go back to the Aviva the following week and Northampton were very clever that day.
"They kicked us into the corner, had a lot of possession, George North eventually scored. They put a lot of pressure on us and we just literally ran out of time. At the end of the game, we were pushing hard, dropped a ball, they ran the length of the field and we lost out on even a losing bonus point.
"That meant we were away in the quarter-final against Toulon which I remember because it was my last game as a player in this competition. There's a huge knock-on effect of every single point in these round robin games. We can't take anything for granted because every point is so important."
Cullen was his usual phlegmatic self after the victory, noting that the team "looked stretched at different stages, particularly in the first half and even for bits of the second half. Northampton had us a couple of times where they don't quite nail that final pass. So, there's lots for us to improve on and it's important we have that mindset."
Leinster trailed 16-14 with less than five minutes remaining in the first half but a 10-minute spell either side of half-time yielded 17 unanswered points and the visitors put the game to bed.
"Leading into the game, we've talked about not quite taking chances that have been there for us in games. Even in the first half, I thought we pushed things a little bit.
"We tightened up a lot better in the second half, we'd much better ball control and two good tries early in the second half and two good tries at the end and that was the most pleasing piece."