Twelve months previously it was Northampton who felt the force of Jonny Sexton's boot in the Heineken Cup final but Munster prevented Joe Schmidt's men from adding the domestic title to their European crown - something never achieved by a Celtic League team and something no-one has managed since London Wasps in 2004.
Leinster can take some solace in the fact that they finished the regular RaboDirect PRO12 season top and were just a Shane Williams swansong score away from their place in history - but Easterby admits that is scant consolation.
"It's hard to put something like that to bed, especially as individuals," said Easterby, speaking at the launch of the 2012-13 RaboDirect PRO12 season in Glasgow.
"Leo [Cullen] was talking about how painful it was when he was still on holiday and how his wife was demanding that he start enjoying his holiday and stop thinking about the final.
"But we see it as we weren't good enough and we need to get better and we have to try to work on getting better every single day and do that up to the weekend and try and win that game and then start the cycle over again.
"The real pain was the players. Particularly this year the Heineken Cup was put to bed pretty quickly and doing something unprecedented against the Ospreys was a pretty big motivating factor.
"The players are the ones that put their bodies on the line and they are the ones who were hurting for a long time after that final.
"It will certainly be a motivating factor this season. The fact of it is that we ran out of steam in the last five or ten minutes of the final and that's something we can't afford to do."
Leinster begin their pursuit of their first Celtic League title since 2008, having lost the last three finals in a row, against Scarlets where Easterby will lock horns with a familiar face following the appointment of brother Simon as the Welsh province's head coach.
After 12 Leinster players were involved in Ireland's summer tour to New Zealand, Easterby revealed the youngsters - who lost a recent pre-season friendly 43-0 to Northampton Saints - will be blooded in the early weeks of the season.
But he believes following the blueprint of GB's Olympic cyclists, who follow a strategy of 'the aggregation of marginal gains' which extracts tiny advantages across the board, will pay dividends.
"It's about marginal gains across the season," he added. "Everyone is talking about [British Cycling performance director] Dave Brailsford and the aggregation of marginal gains but that is what we're striving towards.
"It's relevant because we've proved we're in the mix for these competitions but it's about covering every base to make sure we have the edge and we can turn those one-point defeats in the final at the end of the season into a victory."
"We're very much a week to week team and a process team and the most important thing for us is the Scarlets game and getting that right. There are 23 games before a final and eight games in the Heineken Cup before the final so we can't think too far ahead."
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