"Of course, it's on our minds and we're hurt about what happened. Credit to Leinster, they took their chances and played really well. We'll be aiming to make sure that doesn't happen again.
"We've worked on a lot of things since then and we're a different side. It's such a big game and it's important that we make sure we prepare well and are in the right frame of mind for Saturday."
Leinster currently top Heineken Cup Pool 2 and despite losing away to Castres Olympique last time out in Europe, they have bounced back to win their last four Magners League matches.
Wasps are also in good form, having won seven of their last 10 games in all competitions and Reddan agrees that Ian McGeechan's side have turned a corner since their RDS humbling.
"We're a tighter unit now, but it's much easier to improve when you're in a tight spot," said the Limerick man.
"Back then, we weren't playing well and in terms of results and performances, we could only move forward.
"Whoever wins will be in pole position to qualify. We've got a tough final match in Castres, so we can only think about Leinster. We need a good result, definitely."
Of his prospects of featuring for Ireland in the upcoming Six Nations championship, Reddan was keeping quiet and will hope to let his rugby do the talking.
"I've got no thoughts on Ireland and the Six Nations just yet. This is a club occasion this weekend and I want to just worry about passing, running, kicking and tackling.
"It's great playing in big games because all you need to do is calm down. We'll make sure we're ready but not over eager, you know.
"Leinster travel well, especially on the big occasion, and I can remember when they turned over Toulouse away three years ago. We are expecting a tough and high intensity match."