"We did get a losing bonus point and I guess that that is something but we were disappointed with the result," said captain Denis Leamy.
"We went to the Madejski for the win and we did not get that which is hugely disappointing.
"We did dig really deep to get out from the massive hole we had created for ourselves and get that losing bonus point.
"That is a positive but really it was four points lost and it will be a big challenge against Toulon at Thomond Park.
"However, in this fantastic tournament every match is like one-off game and every one of them is a massive game in its own right.
"This is a must win game - as almost every game is in the Heineken Cup - and we are really looking forward to the game and, hopefully, getting a good result."
Munster have lost their opening Pool game away to an English team and gone on to win the Heineken Cup, going down 24-23 at London Wasps before being crowned champions of the 2007 / 2008 campaign with a 16-13 triumph against Toulouse at the Millennium Stadium.
The Cardiff capital will once again provide the venue for European club rugby's showpiece occasion and Leamy insists the belief they can lift the trophy for a third time is as strong as ever.
"There is the belief we can go all the way, there is a huge belief in our side," he said.
"Against London Irish we were creators of our own downfall in many ways and our discipline probably was not were it needed to be.
"We did give away an interception try which was unfortunate, but these things do happen, and there were a lot of positive things in the way we fought back and got that bonus point. At the end of the day it was something to take away from the match."
In shades of Munster's epic battle at ASM Clermont Auvergne in 2007 / 2008 in particular, when a losing point in a 26-19 defeat was all the difference in even qualifying for the knock-out stages, Head Coach Tony McGahan echoed the value of not leaving Reading empty handed.
"The nature of this group is such that any point you can get away from home is extremely important," he said.
"Heineken Cup history shows that in such a competitive Pool you obviously need to win your home games but if you can fight out your away games and come away with a minimum of a losing bonus point that is very important.
"That means there is a lot of pressure on the home side to get a result - but that is the beauty of the Heineken Cup and why it is a great competition.
"However, we were extremely disappointed at half-time at the way we had played, in particular our discipline, and that is certainly an area we can improve on.
"They played smart and Heineken Cup rugby in tight Pools is Test match rugby - you need to make sure you take your opportunities and, if they are not there, then you release the pressure."