Like all good things, this most welcome marriage between the champions and their trophy must come to an end. This time, the odds are stacked high against Leinster.
For no other reason than Exeter have not conceded four tries to any Premiership club in their 29 matches at home in the highest league in their land.
This is where the experience and acumen of captain Leo Cullen, deposed Ireland captain Brian O'Driscoll and Declan Kidney's new armband holder, Jamie Heaslip, come into play.
Cool heads are imperative. Leinster have to play keep-ball against an untypical English club that does not tend to throw it away too cheaply themselves.
Casting our minds back to the RDS in October, Leinster played into Exeter hands by not being able to get their continuity or tempo up to speed.
The basics are a prerequisite for any Joe Schmidt-coached club. Poor handling and poor decisions in rich positions hampered progress.
Leinster did not master Exeter back then and almost paid the price for it. Argentinian international Ignacio Mieres missing a penalty that would have given Exeter a draw.
Since then, there have been other fallible moments in this campaign. Clermont-Auvergne, of course, have played the part of the villain to perfection. They have been merciless where Leinster have been generous.
The motivation of Exeter does not depend on where they are in Pool Five. They are out of the competition in their first year at this level.
But they have relished the experience every step of the way. This journey will not end until the 80th minute at Sandy Park tomorrow evening.
The Chiefs entered into the Premiership more than two-and-a-half seasons ago with a squad without marquee names and they have taken immense pride in turning over the bigger clubs in England.
The scalp of the European champions would be just another part of their progression at what is a sold-out Sandy Park.
Exeter Chiefs v Leinster
Sandy Park Tomorrow (6.0)
Live Sky Sports 3