It is a peculiarity of the northern hemisphere that the two competitions are run in tandem and, while some profess that the Heineken Cup is the more significant, it's not a belief Reddan holds to be absolutely true.
"RaboDirect games are massive for individuals in terms of getting selected for those bigger games," said Reddan.
"We have a job to do this week. That job isn't to win, really, it is to do certain things that are asked of us, and those standards usually lead to victory.
"We have a massive responsibility, the guys who take to the pitch this week, to be very accurate in everything we do and, if the result comes with that, then great.
"But it's about getting the performance right and working on the specific things that we need to improve on," the scrum-half added.
The desire to add that title to their impressive haul in recent years is a driving factor.
"Even if we had won at the weekend, it is still a massive goal of ours to win the Rabo," insisted Reddan.
"Maybe the fact we lost at the weekend puts a bit more pressure on us to perform this weekend, but even had we won last weekend this would still be a very important game for us."
On Friday night, Leinster travel to Ravenhill to take on Ulster, the one Irish side still very much in control of their European destiny. Leinster are hanging onto their European quest by a thread after losing to Clermont twice.
"They had a very good win the week before and maybe they slipped up against a very determined Northampton side at the weekend," said Reddan of Ulster. "They are probably in a happier position than us. We probably need the win more than them."