And Cullen, who is hoping to see Leinster become the first team to do a European and Magners League double, admits that Saturday's opponents will provide the ultimate test.
Leinster somehow fought back from 22-6 down at half time to beat Northampton last time out but Cullen admits it would be difficult to envisage the same thing happening at fortress Thomond Park.
"Munster have a lot of strong mental strength," said Cullen.
"In terms of comparison to Northampton at the weekend, if Munster had a 16-point lead it is very hard to see how they would have lost. That's the challenge we face.
"I presume they will go into the game as favourites this weekend, being at home and their preparations have been better, but we'll try and give a good account of ourselves when we get down there."
The last time Leinster traveled to Limerick they were on the wrong end of a 24-23 scoreline thanks to Ronan O'Gara's last-gasp penalty.
Cullen and co threw away an 11-point interval lead as their hopes of making it six wins in a row over their greatest rivals came to a frustrating end.
But Cullen insists lessons have been learned from that narrow reverse, lessons that will play a big part in the preparations for the end-of-season showpiece.
"We killed ourselves with the (lack of) discipline in that game," added Cullen.
"We had done well in the first half and were 11 points up at the break. I don't know what went wrong in the second half, but we just didn't perform and ended up giving away far too many silly penalties. We just needed to keep our hands on the ball in the final minute but we conceded another penalty for them to win it.
"We know Munster are a team that are not going to go away. They got stronger and stronger as that game went on.
"We talk of that swing of momentum. We couldn't get a foothold in the game. We got bullied in the contact areas and that's some thing we will look at for this weekend.
"They are a very good side as they have showed in the league, losing only a handful of games. We know them fairly well - not just as rivals but as friends too - so there will be plenty of added spice."
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