There is always something special and emotional when you are playing a game for reasons other than just purely winning some silverware.
Yes, after tripping up to eventual Heineken Cup winners Toulouse, Leinster obviously want the Magners League trophy, but for many in the Leinster squad this game is also about giving some of their team-mates and coach an appropriate, winning send-off.
At the end of this game, veteran players like Malcolm O'Kelly, Girvan Dempsey, Bernard Jackman and others will bid farewell to long and distinguished Leinster careers, while Leinster coach Michael Cheika will also move on to pastures French.
When the affable Aussie coach first came to the province, Leinster proved that they had the talent, structures and personnel to achieve great things; they just needed someone forceful to get them over the finishing line.
The old guard of then Leinster players, such as O'Kelly, Brian O'Driscoll, Shane Horgan, Gordon D'Arcy, Dempsey and others, were asking themselves at the start of each season whether they would ever get their hands on the ultimate European prize, the Heineken Cup.
While some of their former team-mates, like Reggie Corrigan, Victor Costello and Denis Hickie, would never realise that dream, Cheika delivered on his promise, after a shaky enough start.
To his credit, Cheika hung in and, true to his word, delivered Leinster the holy grail last season. In a packed RDS tomorrow night, O'Kelly, Dempsey, Jackman, CJ van der Linde and Cheika will surely do a lap of honour with a tear in their eye, and this emotionally charged feeling and 'playing for your mates' should really spell the difference between two fairly evenly matched sides.
The Ospreys are a star-studded team that have often failed to live up their lofty expectations. Over the years the Ospreys have had the financial clout to attract some of the big names of All Black rugby, including the likes of All Black great Justin Marshall.
Even this weekend their backrow has a strong Antipodean feel to it, with ex-All Black hard man Jerry Collins and former All Black forager Marty Holah teaming up in a different black jersey.
If that wasn't enough Kiwi power, we can also expect the ageless Filo Tiatia to make an impact off the Ospreys bench. There are some marvellous match-ups and cameos in this game, which, given the ground conditions and the forecast, should allow for a fast-paced and exciting encounter.
British and Irish Lions Rob Kearney and Lee Byrne go head to head, as do James Hook and Brian O'Driscoll. Young, international-aspiring out-halves Dan Biggar and Jonny Sexton run the cutter for their respective sides, while the forwards will have a ding-dong battle just for supremacy.
Welsh international James Hook is a real danger man, and regarded as one of the brightest young talents in the world game.
At the tender age of just 24, Hook seems to have been around the rugby block for years, and is able to play in almost every position in the backline as well as kick goals.
It's hard to say what Hook's best position is but, for the moment, and for the Ospreys at least, he has settled in the centre, and poses a real threat to Leinster with a strong fend-off and an ability to read the game better than most, garnished from his days playing at out-half.
The Ospreys have taken a while to adjust to the patterns of play demanded by their unorthodox Australian coach Scott Johnson, but a hard-fought draw with the Leicester Tigers at Welford Road earlier in the season was the catalyst for change and acceptance of what Johnson was working towards.
The Ospreys team like to play a 15-man, fast, offloading game, where the point of contact is constantly changed, but under Johnson they will kick from their own 22 first, often using the prodigious boot of Byrne and the chasing prowess of pocket rocketship Shane Williams and Tommy Bowe.
The problem with the Ospreys is they can be slightly flaky and spasmodic at times, often over-complicating the game when a simple, more structured approach would suit best.
Leinster are probably a more consistent and patient team, often counter-boxing with teams early in the game until they know what they have to offer.
So often, and with a good defence system, Leinster weather the storm, as they did against Munster last week, striking deftly when they get a single chance.
They also have the best game-breakers in Europe, and with just 40pc of set-phase ball they can strike and score from anywhere.
Leinster's player of the season Jamie Heaslip is again vital to their success. Heaslip is now regarded by many as one of the world's best No8s and is the man mainly responsible for getting Leinster onto the front foot.
But, in the ex-All Black duo of Collins and Holah, Heaslip will find the defence systems around the rucks and mauls and at scrum-time a little less porous than he has against other teams.
Heaslip will try and do his damage out wide, where his athleticism and speed is almost unmatched. Collins in particular is the Ospreys' hard man around the fringes of the rucks, and a player well versed at the pick-and-go game in close.
Not quite the abrasive and dynamic player he once was, Leinster will still have to target the man with a hairstyle like a pint of Guinness.
A fascinating battle, but with sentimental value to play for, and home advantage, my money is on the Blues -- just.