"I'm looking forward to meeting Xavier Rush again on the pitch - he is such a strong player," said Kelleher. "Teams need leaders and Xavier's a leader but one person doesn't make a team and it will be the team performance which will make Cardiff tough opposition.
"Obviously we know that Gareth Thomas will be looking to take the victory for Cardiff and he will make sure they are well aware of our strengths and weaknesses.
"That said, the big difference will be Cardiff's mentality. They will see the game as being winnable - even if it's away from home - whereas the French teams have difficulty in believing in their ability to win an away game. A British or Irish team away from home can be just as dangerous as in their own back yard.
"The Blues are playing as a team and when they do that, those individuals will shine. The likes of Tom Shanklin did very well in the Six Nations because the team enabled them to play to their best and, if Cardiff do that on Sunday, then he's definitely a real threat.
"Having the Biarritz Olympique game the weekend before such a huge game wasn't the best preparation for us as we have had a lot of disruption with absent players and Biarritz have a great defence which prevented us from playing our best rugby. Now things are more settled, I think we'll be ready for Sunday's game.
"Despite the 12-6 win, we were disappointed with our performance against Biarritz last weekend, having re-introduced the international players into the squad but with just a short week to prepare.
"Jean-Baptiste Elissalde and myself have been working on the communication side of things and we have some good banter on the pitch which enables us to work together. It was good to play together again.
"Obviously we have a lot of experience between us and were able to both be on the look-out for possibilities for gaining ground or scoring while JB is very good with his boot so having him at No 10 gives us an extra point of attack.
"However, it's a step up for the Heineken Cup quarter-finals. The Top 14 is more of a marathon and not a sprint so we will take the win against Biarritz and move on towards the game against the Blues.
"Because the knockout phases are a totally different ball-game - everyone knows it's an all or nothing game - and now it is down to the really serious stuff. We've re-grouped for one week and now we have to prepare for one of the most important games of the season.
"The intensity has to rise by three or four levels compared to what we produced against Biarritz. I think the attitude is there but we must need to make sure we put the right combination on the field and everyone here is ready to step up to the challenge."