There is an important distinction between unbeaten and unbeatable but for Ulster to find which tag applies to Leinster they'll have to be at their very best this weekend.
The defeat when these two sides last met at the Aviva Stadium - the Champions Cup quarter-final of 2019 - perfectly illustrates the challenge.
Last March, in territory that was unfamiliar if not quite as uncharted as Saturday's PRO14 final, the northern province burst from the blocks and put in one of their best performances of the season despite losing skipper Rory Best to injury.
And yet, come the 80th minute, it was Leinster celebrating - just as they had been after the other five knockout games between these sides since 2011.
Ulster would lose by three but travelled home knowing they had left at least nine points behind them. As well as they played, they had not been perfect.
And, against a team like Leinster, they have learned that perfection is required.
For a more recent example, they need only look to their southern neighbours over the past three weekends.
There was nothing tentative about rugby's first steps out of lockdown at the end of August, Munster v Leinster humming along at a pace that offered no hint of the six-month lay-off that preceded it.
But consider the following - Leinster had only 45% of the ball, lost three of their own lineouts, were whistled for 14 penalties and had all manner of trouble under the high ball.
The post-game chatter was all about everything Munster had done right in throwing the kitchen sink at their gilded rivals.
Fivemiletown man Chris Farrell was awarded the official man of the match award in a losing cause while the likes of Shane Daly, Keith Earls and CJ Stander all drew serious praise too.
Leinster won by two points, stealing the game with a few moments of ruthlessly executed magic. Munster, in contrast, felt like they had to labour for every point.
Two weeks later, in the pro14 semi-final back at the Aviva, things were even uglier. Munster did not register a score of any kind after the sixth minute, missing a few kicks and generally giving the impression of a group banging their head against a brick wall hoping it would give way before they knocked themselves out.
For Johan van Graan's side the frustration must have been not that they were beaten by a generational pool of talent but that they were choked out of the game with Leinster not at their best. They were offered a chance but were not accurate enough to take it.
To have any hope of a PRO14 title, 14 years since their last success, Ulster cannot make the same mistakes.
With the looming threat of Saracens to come in Europe next week, it seems likely that Leinster will go without first-choice half-backs Johnny Sexton and Luke McGrath, and Dan McFarland's side must make life as messy as possible for their replacements Ross Byrne and Jamison Gibson-Park.
Marcel Coetzee, Rob Herring, Jordi Murphy and even centre Stuart McCloskey will need to use all their breakdown nous to spoil things on the deck. If Leinster's back-line are given the time to find space in behind with their new-found probing kicking game, forget about it.
While Jordan Larmour was much improved aerially in the semi-final than in the prior Munster win, measured box-kicks, not always Ulster's strength, must be dropped in on him to ask the tough questions once again.
Too deep, or without a readily arriving challenge, and the Irish international will run them back all night long.
Most importantly, they must seize upon their attacking opportunities. Leinster are not a side you want to give more ball than strictly necessary - they've too many players with too much talent not to give you a difficult day - and it is simply imperative that Ulster are exerting rather than absorbing pressure.
With the back-to-back champions having been penalised 27 times by Saturday's referee Andrew Brace over two games since lockdown, any repeat would give Ulster a platform but too often of late they have found it hard to keep their foot on the throat, basic errors allowing opposition off the hook.
For all the plaudits due for the way they clawed their way back against Edinburgh, their returns from early visits to the opposition '22' weren't just paltry but non-existent. Richard Cockerill's men ultimately wouldn't make them pay but Leinster, with all their Championship pedigree, are a different beast.
The boys in blue didn't lock and bolt the door against Munster - even if it was only left ajar rather than wide open. The challenge for Ulster is to make sure they take any opportunity afforded to them to take it off its hinges and burst through.
Likely? The 11-point buffer the bookies have installed between the teams tells its own story. But possible? Absolutely.
As McFarland himself says, his team will have a puncher's chance. But they better make sure that every time Leinster's guard slips, their best haymakers land.