The tightest Pool in the tournament. Defending Heineken Cup champions LONDON WASPS, double European champions LEICESTER TIGERS and French club BIARRITZ OLYMPIQUE could all finish on 19 points next weekend, prompting some work on the calculator. The Tigers will back themselves to get five points against Rugby Calvisano, but all eyes will be on Parc des Sports Aguilera, with Biarritz needing at least a bonus point to stay in contention. If all three teams finish on 19 points, their results against Calvisano are initially ignored and the final Pool placings depend on the match points earned in matches between the trio. If that doesn't separate them, it goes down to tries scored in those games, and then points difference. For the record, Biarritz have scored four tries against Leicester and Wasps; Wasps have bagged five against Biarritz and Leicester, while the Tigers are on nine tries - with no chance of increasing that figure next weekend.
Possible scenario: Biarritz stormed into title contention with their win over the Tigers at Welford Road, and have the best chance of topping this Pool with a draw or win against London Wasps. If all three sides finish on 19 points, the Tigers come into contention with their superior try count.
LEINSTER are the first team to qualify for the quarter-finals, but will be looking for a Lansdowne Road victory over BENETTON TREVISO to guarantee the No 1 ranking. For their part, Treviso would move to 19 points with a shock bonus-point victory at Lansdowne Road, but that's unlikely to be enough to make them the first Italian quarter-finalists in the competition's history. Bath Rugby and Bourgoin are out of contention.
Possible scenario: Leinster should beat Treviso and take the No 1 ranking with 25 or 26 points. If that happens, they will be the only qualifiers from Pool 2.
Last season's runners-up TOULOUSE need a win at home to the Llanelli Scarlets to ensure qualification for the quarter-finals, but even a close loss leaves them in good heart. NORTHAMPTON SAINTS host Glasgow Rugby, knowing a bonus-point victory would move them to 21 points, and both they and Toulouse could progress from this Pool. The Saints' last-gasp win at Stradey Park has knocked the Scarlets out of contention.
Possible scenario: Toulouse will be favourites to beat the Scarlets at Stade Ernest Wallon to win the Pool The Saints will be reluctant favourites to beat Glasgow, giving them 20 or 21 points and in the driving seat for a quarter-final berth as one of the two best runners-up.
MUNSTER are in the box seat in Pool 4, knowing a victory over NEC Harlequins guarantees them a quarter-final berth. CASTRES OLYMPIQUE are in contention for one of the runners-up spots, but face a tricky trip to the Neath-Swansea Ospreys. If Munster slip up against Quins, Castres can top the Pool with a win over the Ospreys.
Possible scenario: Harlequins' defence against Castres in the final 30 minutes at the weekend doesn't bode well for their chances of upsetting Munster, and the perennial Cup quarter-finalists are favourites to make it through. The game between the Ospreys and Castres Olympique is to close to call, but Castres undoubtedly have more at stake.
NEWCASTLE FALCONS have Pool 5 at their mercy, but have to beat NEWPORT GWENT DRAGONS to ensure qualification. A Dragons win moves them into contention, with PERPIGNAN also moving into the calculations if they beat Edinburgh in Scotland.
Possible scenario: The Falcons will be without Jonny Wilkinson and this is the hardest Pool to predict. Perpignan haven't travelled well, but have the possibility of securing five points in Edinburgh, which would see them in the hunt for either Pool winners or a best runners-up spot, depending on the outcome in Newcastle.
STADE FRANCAIS PARIS lead Pool 6 by five points, but they have to travel to GLOUCESTER, who will be running the ball from everywhere to earn a bonus-point win to go level on points. If that happens, it will come down to tries scored in the two matches between the sides, with Stade holding a 5-3 lead after their Round 1 victory. Ulster can move to 17 points if they beat Cardiff Blues and score five tries, but that won't be enough to qualify as runners-up.
Possible scenario: Stade know they need only a point at Kingsholm to ensure qualification but will be going all out for home advantage in the quarter-finals.