Monday 23 January 2017 12:45, UK
We look at what each team needs from the final round of the Champions Cup in order to make the quarter-finals.
Here's how the seedings currently look after five rounds:
But what does each team need in order to progress to the quarter-finals? We've broken it all down for you...
Munster v Racing 92
Munster wrapped up Pool 1 with victory over Glasgow at Scotstoun but they need to beat Racing 92 at Thomond Park to guarantee a home quarter-final.
Even if they lose to Racing, Munster could still get a top-four seeding but they would require other results to go their way. Rassie Erasmus will hope his side can eliminate any need to bring out the abacus by beating their visitors on Saturday.
Racing 92 are out of play-off contention after losing four out of their five group matches but will be looking for revenge after they were thrashed 32-7 by the Irish province in their rearranged fixture in Paris earlier this month.
Leicester Tigers v Glasgow Warriors
The Tigers can't make it into the play-offs even if they beat Gregor Townsend's men, following an indifferent European campaign from the two-time champions.
Meanwhile, second-placed Glasgow will claim a runners-up spot if they knock over Leicester at Welford Road. In fact, even if the Warriors lose they could still sneak through if they pick up bonus points and other results go their way.
Zebre v Wasps
In reality Wasps are likely to take all five points against the Italians, who have shipped 43 tries in their first five outings in the competition.
If Wasps do claim five points, and Toulouse win or Connacht beat Toulouse but don't score four tries in the process, then Dai Young's side will finish the group stages at the top of the table due to their head-to-head superiority over Connacht. If Connacht win with a bonus point against Toulouse, then the Irishmen will top the group regardless of what happens in Italy.
Toulouse v Connacht
Buckle up; this one's complicated.
Let's start with the easy part: if Toulouse fail to win, they are out of the Champions Cup. No amount of losing bonus points or results in Italy can save them if they are beaten by the men from Galway, or if they draw.
As for Connacht, their fate is far more fluid; a win of any kind would see them progress to the next stage but it wouldn't necessarily guarantee them pole position in Pool 4.
If Connacht win with a bonus point then Wasps can do nothing to catch them. Win without a bonus point and Wasps do the same, then Connacht still finish top. Win without a bonus point and Wasps claim all five against Zebre, then Connacht take one of the runners-up places.
And it gets even more complicated…
As Connacht are four points ahead of Toulouse, there are several scenarios in which they could lose and still make the knock-outs. If they lose by seven points or fewer and Toulouse win without a bonus point then Connacht progress. If Toulouse win with a bonus point then Connacht can still finish ahead of the Frenchmen if they score at least four tries and lose by no more than seven points.
If the two sides end up on the same amount of points on the table after six rounds then it goes to head-to-head matches between the pair; first on competition points, then points difference, then tries scored. Connacht's 23-21 win in Galway - scoring three tries to Toulouse's two - gives the Irishmen an edge in all three categories.
Sale Sharks v Scarlets
Scarlets would have been in the mix for a play-off spot if they had held out against Saracens on Sunday. As it is, Chris Ashton's last-gasp try at Parc y Scarlets means it is now impossible for the west Wales side to progress.
They are currently five points behind Toulon, and even if they drew level with the French side with a bonus-point victory, they would lose out based on the head-to-head results between the two clubs.
Sale, with no wins from five outings in Europe this season, are playing for pride alone.
Saracens v Toulon
Just as above, this game would have been made all the more interesting had Saracens left Wales with a losing bonus point alone.
As it is, there is only one way for Toulon to guarantee usurping Saracens this weekend - the French outfit must win with a try-bonus point and ensure that Saracens get nothing out of the game.
As Saracens failed to claim a bonus point in their round-one win in the south of France, they would lose out on top spot in the head-to-head, but would still be one of the three runners-up overall.
Aside from who tops the pool, Saracens will still progress regardless of any of the weekend's results, while Toulon need two points at least - a draw or two bonus points in a loss - to guarantee one of the runner-up places.
Castres v Leinster
Leinster are the number one seed as everything currently stands. Their complete domination of Pool 4 means a bonus-point win against Castres will most likely be enough to top the standings at the end of the weekend. Clermont could still have something to say about that, but that something would have to be a victory over Exeter by close to 100 points.
Castres still have a slim hope of qualifying as one of the three best runners-up, but first they need to pick up five points on Friday. In the other match in the group they need Montpellier to lose against Northampton, and beyond that they need Toulon and Bordeaux-Begles to be heavily restricted by their opponents.
Montpellier v Northampton Saints
Saints have been the perennial strugglers of this season's European campaign, which means they need a miraculous series of events if they are to qualify for the knock-outs. For starters they need five points against Montpellier. They then need Glasgow to lose to Leicester by roughly 130 points, they need Leinster to beat Castres, and they need Exeter to lose to Clermont. In the game between Bordeaux and Ulster, Saints need the Irishmen to win without a bonus point to eliminate both teams from contention.
Montpellier have a better chance of sneaking through the door in seventh or eighth place overall but they need to win with a bonus point, hope that Exeter don't do the same, and they need Toulon to come away empty-handed from Allianz Park.
Ulster v Bordeaux-Begles
Bordeaux-Begles are in the same boat as Castres; relying on results from domestic rivals. The visitors have to get five points at Kingspan Stadium as a starting point and hope that Castres are restricted to a win without a bonus point at least.
Additionally, Bordeaux have to hope Toulon get no points out of their Saracens fixture and end the weekend with an inferior points difference to themselves.
Ulster can progress to the next stage, but they would need Glasgow to get beaten by a margin nearing 60, and they need Northampton to beat Montpellier but not with a try-bonus point. They also need Castres to lose to Leinster and Exeter to lose to Clermont.
Clermont Auvergne v Exeter Chiefs
Exeter, one point ahead of Bordeaux, are in a slightly better position. Win with a bonus point - easier said than done at Stade Marcel-Michelin - and they take Castres and Bordeaux-Begles out of the equation.
If Toulon lose without any bonus points against Saracens and Glasgow pick up only one bonus point in a loss to the Tigers, then the Chiefs - much as they did last season - will wriggle their way into the quarter-finals just as the door is closing.
Clermont have already qualified for the last eight and victory over Exeter will secure a home quarter-final, and possibly a No 1 seeding.
