For all of the thrilling attacking rugby that Leinster played during their demolition job over the Scarlets in last month's Champions Cup semi-final, the foundations for the resounding victory were based on their relentless aggression at the breakdown.
The talk from the Scarlets camp all week has been about matching Leinster's physicality in this afternoon's Guinness PRO14 final, but it is one thing recognising it, and another actually doing it.
Very few teams have been able to cope with the European champions this season, and while the Scarlets will feel that they owe Leinster one, they will need to improve immeasurably across the board, if they are to have any hope of defending their title.
John Barclay is a huge loss for the Welsh side, and his absence means a positional switch for Tadhg Beirne, who starts at No 8.
The Kildare native has played the majority of his rugby this season in the second-row, with several cameos in the back-row, but it isn't often that he finds himself at the tail of the scrum.
It's as much a testament to Beirne's flexibility as it is about Wayne Pivac wanting to pick an ultra-dynamic back-row that he believes can cause Leinster problems.
Between them, the trio that start in the back-row have managed a staggering 59 turnovers this year.
Beirne has once again been a constant menace at the breakdown and he is comfortably out on his own at the top of the charts with an impressive 37 turnovers. Aaron Shingler has racked up 12, with openside James Davies just behind him on 10.
"They played us off the park, especially in the back-row, and I'd be the first to admit that," Davies admitted earlier this week.
The return of Dan Leavy is crucial for Leinster. The former St Michael's College student destroyed the Scarlets last month and is in the form of his life.
Pivac might have expected the outstanding Scott Fardy to start alongside Leavy in the back-row but when you have such a luxury of riches as Leinster do, removing one of their best players this season and replacing him with someone of Rhys Ruddock's calibre certainly does not weaken the pack.
So much has happened, both with club and country, since Ruddock tore his hamstring back in December, that it is easy to forgot that the 27-year old was arguably the form Irish flanker before he missed several months.
Getting through a huge shift against Munster last week will have done Ruddock the world of good, but he will know that he will have to go up a level against this Scarlets back-row.
In Leinster training this week, and before the Champions Cup semi-final, an Academy player wore a blue scrum cap to replicate Beirne.
It's an unenviable task in truth, because as we saw on the Scarlets' last trip to Dublin, they targeted Beirne every time he attempted to put himself in the jackal position to poach the ball.
The game was barely a minute old before Beirne expertly executed a choke tackle that forced a turnover, but anyone who thought that was a sign of things to come was wrong.
Devin Toner doesn't often get the plaudits that his consistency deserves, and that is made all the more difficult by playing alongside an all-action wunderkind like James Ryan. Toner, however, was outstanding against the Scarlets and laid down his own marker early on.
A hallmark of Leinster's play that day was to commit three players to the breakdown in order to stop Beirne and co getting into position.
In example 1, Rob Kearney has taken the ball into contact and Beirne (yellow circle) thinks he can steal it, before Toner and Garry Ringrose smash him in contact, with Fergus McFadden (green circles) also quickly on hand to help out.
Ken Owens (blue) is trying to heap pressure on referee Romain Poite but the captain's plea falls on deaf ears.
A similar scenario unfolds in example 2. This time Robbie Henshaw has made ground and Davies (yellow) attempts the poach but Toner, Seán Cronin and Cian Healy (green) ensure that Leinster recycle the ball.
Again in 3, Toner plays a crucial role. Beirne (yellow) gets into a very good body position but the towering Leinster lock, along with Tadhg Furlong and Healy (green) are brutally effective in how they nullify the threat of their former team-mate.
Rob Evans (blue) is playing Owens' role as he is now insisting that Beirne has forced the turnover. Again though, Poite is not interested.
Finally, example 4, highlights the period just before half-time, when Leinster effectively won the game.
Beirne is again in the mix but it's his team-mate Davies (yellow) who gets in the jackal position, only for Furlong, Fardy and McFadden (green) to clear him out, despite Evans' (blue) appeals.
All of these situations occurred during the first half, which was arguably Leinster's best 40 minutes of what has been a stunning season.
They will look for another rip-roaring start today, but the Scarlets will have done their homework.
It's difficult to imagine the Welsh side not firing a shot this time around, yet even if they do, it will take a mammoth effort at the breakdown to stop Leinster laying the platform for winning an historic double.