London Wasps may be marginal favourites to emerge triumphant from the three-way Pool 6 dogfight but their star Welsh scrum half Robert Howley knows it is going all the way to the wire.
"We have all done our maths and our homework and we know that if we win in Perpignan we will be in with a good chance of getting a home quarter-final draw," he said.
"That would be brilliant because we all know that a packed house at home is worth five to seven points start to any team. There have only been six away wins out of 28 quarter-finals to date in the Heineken Cup.
"There is everything to play for and at this stage we will be more than happy to come out on top of the Pool. We physically dominated Perpigan at home but we were guilty of only playing for 60 minutes. If we are going to win in France then we will have to play for the full 80.
"That home defeat to Celtic Warriors was a real dent, but we are now back on track. A lot will depend this weekend on how Perpignan react to their defeat at Celtic Warriors. We are going out there to win, but I am sure they are going to be pretty fired up as well."
Meanwhile, Gareth Thomas' Celtic Warriors travel to Italy to face Calvisano on Sunday knowing that another five points would take them to a maximum of 20.
There is a possibility of all three teams finishing level with 20 points at the end of next weekend - Warriors getting a bonus point in Calvisano, Perpignan beating London Wasps with four tries and Wasps getting within seven points in France in defeat - and the calculators being essential equipment.
But Warriors coach Lynn Howells is not going to let the maths get to him as he builds towards another huge weekend. He just wants to stay on the winning trail.
"There is still everything to play for in this Pool," he said. "In some ways I'm glad that Perpignan got a bonus point at the Brewery Field because it means they can still qualify by beating Wasps next weekend.
"What we must ensure is we get a result in Calvisano and do everything to earn a bonus point. Both those targets will be difficult. Perpignan only just beat Calvisano in Italy and scored four tries against Wasps."
The last-gasp victory over Perpignan, last season's beaten finalists, provided further proof of the development of the Warriors both on and off the field. Another healthy crowd made their presence felt and the team never threw in the towel.
"I have to admit that I thought the result had gone from us. We had so many chances to score, yet we didn't take them," said Howells. "I was annoyed the previous week that, having done the hard work in beating Wasps at High Wycombe, we didn't finish off the job and win at home.
"The team did extremely well to hang on in to the bitter end and we have to remember they have only played a handful of games together. There is a lot of work still to be done, but there are encouraging signs.
"This was a result that could so easily have passed us by. I thought the referee's decision on the penalty try was very fair but we could and should have had the game won well before that."