Jonathan Sexton is well aware of the challenges that await and given the see-saw nature of last season's battle fresh in the memory, he knows that Michael Bradley's men are going to be a powerful force at home in Murrayfield.
"Edinburgh find themselves in a similar position to ourselves, prior to last weekend's victory over Connacht, where we were coming in off the back of a few narrow defeats.
"Games against them are always tough and form goes out the window. Having won the Heineken Cup back-to-back over the last few years we have learned that we're a scalp for other sides and they raise their game against us.
"They tend to go up a level, irrespective of their league position, so we can never be complacent and that's why we approach every game on its own merits.
"They have real threats out wide - the likes of Tim Visser has been an exceptional finisher for them over the last few years - and they have big ball-carriers up front.
"Yeah, it's fair to say that this is a really good test for us coming into a huge month in the context of the league and Europe."
Having played in Murrayfield for province and country he is expecting another fiercely competitive battle.
"I've played there in two internationals, one of which was a World Cup warm up and the other was a Six Nations game," he said.
"And whenever you face Scotland there the atmosphere is brilliant to play in. It can be a bit strange then playing Edinburgh when the crowd is a fair bit smaller, but Edinburgh have been enjoying some really good crowds over the last few months, especially last weekend in their return match against Glasgow.
"Obviously coming off the back of their brilliant run in Europe last season, all the way to the Heineken Cup semi-finals, that seems to have captured the imagination of the public."
Sexton was given a break over the holiday period and the Ireland out-half is "feeling fresh" and "looking forward", as he declared on the eve of tonight's showdown.
"On the one hand it's nice to get a break after a demanding last few months, but you never like missing big matches, especially against the other provinces at this time of the year. So after the Round 4 game against ASM Clermont Auvergne I had a tough week's training and then managed to get five days off before Christmas.
"I wouldn't be the best spectator, but watching from the sidelines I was hugely impressed by the efforts of a lot of the younger lads especially against Connacht last weekend.
"Maybe it wasn't the flashiest of games, but there was a lot of character and resolve displayed by the lads and we can take some important positives and aim to build on them this week.
"That kind of character and resolve, in keeping a side like Connacht to nil on the scoreboard in what were really tricky conditions, was impressive.
"I'm really looking forward to the next few weeks because they're going to go a long way to defining our season."
After Edinburgh Leinster face into two massive games against the Scarlets and then Exeter Chiefs.
The St Mary's College playmaker believes that the return of several front-liners can boost the province as they gear up for a series of big tests.
"If you look at it historically, you'd be unlucky not to get through on 20 points. We have to be positive and we know that we have to try and get the win because when you start looking at bonus points you can sometimes lose focus. And a win against Llanelli is hard enough without worrying about anything else!
"We nearly beat Clermont away three weeks ago and the margins are so fine at this level. The teams we need to slip up have some big games and we will try our hardest to put ourselves in the best possible position to qualify should that happen.
"It's great to have the likes of Brian (O'Driscoll), Lukey (Fitzgerald) and Rob (Kearney) back and it will be like a raft of mid-season signings with others like Dave Kearney and Eoin O'Malley set to come into the frame too.
"The lads were all looking really sharp in training on Monday morning and just having them back in the mix has given everyone a lift.
"We've missed them around the place and their quality on the pitch can give us an important boost as we face into this big month."
Any New Year's resolution? And then there's a slow, careful and considered pause. "January is the most productive month for a lot of people.
"There are a lot of good intentions as people make promises to themselves. But for us in Leinster, it's about starting off well in January and pushing on from there. We see ourselves as a week-to-week team and we don't look past what's in front of us. So while players might have short- and long-term goals, it's about working hard and applying ourselves day in and day out."
And with that Sexton is off. A new and challenging year begins.