Northampton Saints are firmly in control of Pool 1 but Castres are not out of contention for more European action in April, whereas the Blues will need results to go their way in other groups if they are to maintain their interest in European competition through the Amlin Challenge Cup again.

Castres celebrated a 27-20 home victory over the Blues in Round 2 but French international scrum half Alexandre Albouy believes they must contain the Blues if they are to clinch that double and stay in the hunt for quarter-final qualification.

Albouy said, "The challenge will be to stop them up front and try to prevent them from getting hold of the ball. We will have to produce momentum of our own and spread them across the field."

"Like Edinburgh, the Scottish side in our group, [the Blues] have that ability to hold on to the ball for a very long time so it is extremely exhausting for the defence. We will have to be vigilant and not allow them to gain territory and avoid turnovers when we are in possession.

"On top of that, their half-backs are really good at directing their team-mates and recycling the ball, so it helps in adding to the phases of play. They have a varied game and a fantastic pair of explosive centres who push their team forward - they know how to make the most of their assets."

Castres did pick up a losing bonus point at Murrayfield in Round 4 but they let three points slip from their grasp when Simon Webster scored a try for Edinburgh in the 77th minute and David Blair converted to claim the points.

"Our defeat in Scotland drastically reduced our qualification chances and they are pretty slim judging by the results obtained in other Pools," said Albouy.

"The Round 2 match against the Cardiff Blues in Castres ended in our favour but they led during one period and we led during the other so our next European fixture on Friday night is a fantastic occasion to face a great team and hopefully achieve a great performance.

"And, if we are lucky, we will perhaps get a result that will put us back on track, although knowing that we would still have to beat Northampton Saints at the last hurdle to make sure we still stand a chance of qualifying.

"We will approach Round 5 as being a massive encounter, but we won't put ourselves under the pressure of having to qualify because it is too uncertain at this stage.

"We are delighted to have got back into the Heineken Cup this season after having created something of a surprise in our domestic league last year by finishing fifth, but the start of this season was tough because we were put under the microscope and people expected a lot from us.

"The level of the Heineken Cup is definitely higher than that of the Amlin Challenge Cup but overall I think we have confirmed we have our place on merit in this competition. Even though our current Pool situation is shaky we are on the right path towards improvement and there is still a glimmer of hope to spur us on."

Final Pool 1 Fixtures - Saturday 22^nd January 5.45pm GMT

Castres v Northampton Saints
Edinburgh v Cardiff Blues