A MEETING of first against third, an Irish derby and a rematch of last year's Heineken Cup final. Throw in the fact that it is the last Friday night before Christmas and the celebrated Ravenhill atmosphere, and tonight's game should have been one of the highlights of the season.
Then along comes Declan Kidney with his best 'Scrooge' hat on and away goes the magic. Jonathan Sexton has been withdrawn from the Leinster line-up and suddenly the focus switches from whether the Heineken Cup champions can continue their winning run over Ulster to how much the hosts can win by – especially with the news that Isa Nacewa and Shane Jennings have lost the race to be fit.
The Ireland fly-half is being wrapped in cotton wool for the Christmas period, leaving Leinster shy of experience behind the scrum. And so, what was an eagerly anticipated clash has become diluted and the Pro12's reputation suffers once again.
This should be where the competition shines brightest, but with the IRFU management plan dictating the use of players, these derbies are becoming mismatches.
Despite their long injury list, and Darren Cave, Craig Gilroy and Roger Wilson's stomach bug problems this week, Ulster are as near to full strength as is possible.
Even with their disrupted preparation, the northern province should be eyeing a restorative win after last week's first defeat of the season against Northampton.
Mark Anscombe has picked his strongest available team for tonight and will take the hit against Munster next week.
The system is frustrating for coaches, fans and even the players. Sexton is rested despite having attempted to convince Kidney that he would prefer to play.
"I know it's for our sake, at the end of the day," he said. "I said this to Declan. It can get a bit complicated... If I pick up a niggle in two weeks' time or you have a game off or you're out for a couple of games... and then you haven't played for four to six games.
"That happened two seasons ago. I was rested for the first two, then picked up a niggle and missed the first six games of the season. That's where it can be frustrating, especially for me, because I always start playing better when I've had a run of games. You're beginning to find your best form and then you have a break again."
Sexton's boots will be filled by Ian Madigan, who returns to the No 10 jersey after a spell at full-back.
Another fly-half, Noel Reid, starts in his place at 15, with Andrew Conway on the wing. Brendan Macken replaces Andrew Goodman in the centre, with Gordon D'Arcy switching inside, while Kevin McLaughlin returns to the fray in the back-row in Jennings' place, while Cian Healy, Sean Cronin and Michael Bent start up front.
Ulster's side shows four changes from the team who lost to the Saints. Despite his stomach problems, Gilroy replaces the injured Tommy Bowe, while Neil McComb comes in for Dan Tuohy and Robbie Diack starts on the blindside to allow Wilson a rest after he suffered from the bug.
Luke Marshall gets a run in place of Paddy Wallace.
There is plenty of motivation for the northern province, who have lost their last seven meetings with the European champions and have won just once in 18 games.
Their last meeting was the Heineken Cup final when Joe Schmidt's men overran the men in white at Twickenham, but winger Gilroy believes that tonight will be different.
"A lot has changed since then," he said.
"It is a derby, it's Leinster, you don't have to build up to a game like this. It's as big a game as you get.
"Darren Cave was saying we've only beaten them once in the last 18 games, so we're keen to address that.
"We're keen to put a marker down.
"Obviously, we want to bounce back from the Saints defeat. We won't face a tougher test than Leinster.
"They have lost a couple, so they will be gunning for us."
Given the spate of injuries which is keeping so many of his frontline players out of action, Schmidt must be cursing Sexton's withdrawal for this crucial game. Leinster trail Ulster by 12 points at the top of the table after 10 games and it seems unlikely that they'll make up ground tonight.
A losing bonus point would represent a good result for the visitors, who have not lost three games in succession since 2010.
In front of their home crowd and after suffering a first loss of the campaign, Ulster want to make a statement and they should deliver.
ULSTER – J Payne; A Trimble, D Cave, L Marshall, C Gilroy; P Jackson, R Pienaar; T Court, R Best, J Afoa; I Henderson, N McComb; R Diack, C Henry (capt) N Williams. Reps: R Herring, C Black, A Macklin, A O'Connor, R Wilson, P Marshall, P Wallace, A D'Arcy.
LEINSTER – N Reid; A Conway, B Macken, G D'Arcy, F McFadden; I Madigan, E Reddan; C Healy, S Cronin, M Bent; L Cullen (capt), D Toner; K McLaughlin, S O'Brien, J Heaslip. Reps: A Dundon, H van der Merwe, J Hagan, T Denton, R Ruddock, I Boss, A Goodman, A Byrne.
REF– G Clancy (IRFU)
Ulster v Leinster,
Live, BBC1/RTE 2, 7.05