Leinster meanwhile welcomed back a number of their Ireland internationals in a 27-0 bonus-point win over Zebre - a result that kept them top of the RaboDirect PRO12.
A number of Munster's Irish contingent had to watch on as the international side had a successful period in February and March without their help.
But Penney believes his side will benefit from focusing all their efforts on working as a team instead of looking to impress individually.
"It is going to be really, really challenging. They have a group there who have been conditioned to Test matches," Penny told the Irish Independent. "We have a group that have played no rugby basically for three weeks.
"The odds are stacked and you would expect the team that has had the ability to be conditioned to Test match rugby to be fresh and excited about the opportunity to put the blue jersey on at home.
"The game will be a massive occasion and we just have to make sure we are disciplined and that we are playing for each other.
"We have to put all the individual battles to one side because that is going to be a distraction that we don't need.
"We have got to make sure that collectively we are on the same page and that we are working hard for each other and Munster. That is our best way of combating what they will bring."
63x46.png){kind=logo}