While this year Leinster have failed to secure a top-four finish, throughout Townsend's reign the Irish team have proved a thorn in his side.
In 2013 Glasgow lost at the semi-final stage to Leinster and last year they returned to the RDS in the final only to suffer a 34-12 defeat at the hands of Matt O'Connor's men.
And Townsend admitted when he first took charge at Scotstoun he was eager to model Glasgow's style of play on the all-round dominance of both Leinster and world champions New Zealand.
"Before I came into the job the teams I looked up to as role models were Leinster at club level and the All Blacks at Test level and those teams move the ball," he told the Irish Times.
"If you really want to win the big games you really have to have an all-round game.
"If we were to score five tries but lose because the defence was poor or loose or undisciplined then we'd change the way we play.
"Now, there can be more mistakes when you try things. As long as they are mistakes that are pushing the boundaries or plays we can learn from other than sloppy mistakes, then we'll continue to improve.
"You don't win games unless you have a very good defence and we put a lot of pride in our defence and a lot of work into it."
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