"It is a great game to get under out belts, between two of the best teams in Europe, I feel," said Leamy.
"There is work to be done but it is not all bad.
"What do we do? We can't dwell on it. We've had a decent start. We came up here to win the game but that didn't happen. Leinster probably just deserved it.
"We'll take the positives and move on. We have to. We have no other choice."
Munsterwill be hoping to return to the scene of their last European triumph in 2008 when the Millennium Stadium hosts the Heineken Cup final on May 21, 2011 but first they must make it out of arguably one of the toughest pools in the competition's history.
"The next two weeks are massive. If we get two wins we are set up because it is a really tough group," added Munster wing Johne Murphy.
"We are going to learn a lot about ourselves when we look back and review our game and see what we need to do against London Irish."
Munstertravel to Reading to face the Exiles on Saturday in their first Pool 3 fixture before welcoming last season's Amlin Challenge Cup finalists RC Toulon to Thomond Park the following week.
When the Heineken Cup returns to action for rounds three and four in December the Irishmen face Magners League Champions the Ospreys in back-to-back fixtures, starting at the Liberty Stadium.