This is all set up for one of those special nights when the character of one or other force will win out.
After the Ospreys beat the Scarlets and Glasgow Warriors' defeat of Edinburgh over the Christmas period, Ulster have dropped to fourth in the RaboDirect PRO12 table, six points behind leaders Munster; Leinster are fifth, a point further back.
You don't have to be a mathematician to work out that a victory for either province will take them into second on the ladder.
Leinster have not played to their standards in the last two matches. Coach Matt O'Connor will set his stall out to maintain their accuracy in defence and transform it in attack.
"I think we've got to get better parity at the set-piece," he said. "We've got to defend better. We've got to look after the ball. They are probably the three biggest things in the last couple of weeks where we've let ourselves down."
The best laid plans can be laid to waste. Logic dictates that the weather will play a central role in how Leinster go about asserting their dominance.
"You can't be turning the ball over with handling errors and inefficient stuff at the breakdown against very good sides," he said.
"The boys understand that. They're not real happy with what they have delivered individually and collectively over the last couple of weeks."
The past two matches are in the past. They can't do anything about those now. But, they can use them as a tool to right the wrongs they have perpetuated.
The same could be said about Ulster. The drab victory over Zebre last weekend was one of those games where they had to win it and forget about it.
O'Connor preferred to tout the positives of the Italians than the negatives of Ulster: "Zebre are better, I think, than people give them credit for.
"They've certainly developed a resolve that they haven't had before. They've brought in a couple of players that have given them a bit of steel. They're not easy-beats."
Once the professional courtesy towards the Italians had been dispensed, O'Connor warned that the Ulster of tonight will bear little or no comparison to that evening.
"I wouldn't read too much into that performance. I think they will come on Saturday to try and get the result. We've got to make sure we're really good."
There is compensation in the immediate impact of Zane Kirchner, the hot form of Rhys Ruddock and Jordi Murphy and the return of the combustible Sean O'Brien.
Leinster have been hampered by the Ireland Player Welfare Management Programme to a greater degree than Ulster. It could prove crucial.
How does O'Connor compare Ulster to the side which damaged Leicester Tigers so badly in the Heineken Cup last season?
"They're probably the same strengths. They're probably a little bit better in relation to understanding what they want to achieve as a team and getting the best out of Ruan Pienaar and the other special individuals they've got in their group.
"They're all contributing pretty well and they've shown in Europe and in the Rabo they're a very tough team to break down. We're going to have to make sure we take our chances and are very, very clinical."