The Blues and Edinburgh are level on 13 points with Edinburgh topping Pool 2 courtesy of a superior overall try count, but thanks to a losing bonus point at Murrayfield the Welsh club are 5-4 ahead in match points from their back-to-back meetings with the Scottish club in Rounds 3 and 4.
"The nicest thing about going into our last two Pool matches is that it is all about us," said Blues forwards coach Justin Burnell.
"Because it is pretty straightforward that if we want to qualify for the quarter-finals then we need to beat both London Irish and then Racing Metro 92.
"So it all starts at the Madejski on Saturday and, whatever number Heineken Cup game it is for us, the focus on the day will be entirely on the big event - trying to get the W.
"Both London Irish and Racing can have major impacts on our group and we are well aware that London Irish are a very good side. As well as that they will be at home so they will play with plenty of pride in front of their own fans.
"We did beat them 24-18 in our home match in Round 2 but their red card certainly had a big bearing on things and, as is so often the case, we felt we played better against 15 than against 14. However while we were pleased with that result we were disappointed with the Edinburgh game, though we did manage to come away from Murrayfield with at least a point.
"If it does come down to the two games between us then that point could be invaluable.
"Overall we are happy enough where we are as a club at the moment as the new coaching team of myself and Gareth Baber try to move us forward under the change in style - the plus points of that switch being the tries scored and bonus points won."
The Blues will become only the sixth club to reach the 100-game tournament milestone.