We're getting to the business end of the European club rugby season now. This weekend will see confirmation of which teams will make up the eight Champions Cup quarter-final spots. And, unsurprisingly, the permutations regarding which teams will make the knockout stages are far from easy to understand. After all, there are 11 teams battling for five berths, how was that ever going to be easy to get your head around?

Luckily we’ve pored over the points, bonus points, tries scored, tries conceded, head-to-head record and beyond to make the whole process a lot easier.

Firstly, Leinster are out no matter what happens. We've known that since the week before last but they can still have an impact on who makes the quarter-finals. It is more than likely Ulster who willl hope to plough the lone Irish furrow on the way to Lyon, although Anthony Foley's Munster team do still have an outside chance of making it but it's highly unlikely.

Let’s start with the basics. There are five pools in total with the five pool winners and the three best runners-up making the quarter-finals.

Teams from different pool who are tied for a best runner-up spot will be separated by the following criteria: 1. Best points difference; 2. Tries scored; 3. Fewest players suspended; 4. Draw lots.

Saracens in Pool One (Ulster’s pool), Racing 92 in Pool Three and Leicester Tigers in Pool Four have already qualified as pool winners.

Pool Two is the closest of all with all four teams still in with a chance of going through while in Pool Five it is between Toulon and Wasps for top spot.

Confused yet? We haven’t even got to Ulster.

So let’s look at what the Ravenhill side need to do to make sure they reach the knockout stages.

Les Kiss’ side take on Oyonnax at 1pm on Saturday while Toulouse welcome Saracens.

Ulster are guaranteed second place in their pool but anything less than a bonus point win against Oyonnax in Belfast will see them miss out on one of the best runner-up spots.

That bonus point win would move them to 18 points. Of the other teams looking to occupy a best runner-up spot, six can pass Ulster’s total of 18 points.

Those teams are:

Pool Two – Ospreys (final fixture v Exeter Chiefs away) and Clermont Auvergne (final fixture v Bordeaux-Begles at home).

Pool Three – Northampton Saints (final fixture v Scarlets away).

Pool Four – Stade Francais (final fixture v Leicester Tigers at home).

Pool Five – Toulon (final fixture v Bath away) and Wasps (final fixture v Leinster at home).

Pool Two is too close to call with all four teams still in with a chance of qualification. Ulster’s best hope is that Ospreys beat Exeter – therefore topping the group – and Bordeaux beat Clermont Auvergne – therefore finishing second but with less points than Ulster even if they get a bonus point.

In Pool Three Northampton will be expected to beat bottom of the pool Scarlets with ease. Were the English side to beat them with a bonus point they would reach 19 points and surpass Ulster. If they win and fail to get a bonus point it will come down to points difference between them and Ulster. Currently Ulster’s points difference is +7 while Northampton’s is -11.

Moving on to Pool Four it’s a similar situation with Stade Francais on 14 points – the same as Northampton but with a far superior points difference (+53). Incidentally, if Munster beat Benetton Treviso with a bonus point and Stade Francais lose to Leicester, Munster will finish second with 15 points – most likely not enough to take a best runner-up place.

In Pool Five Toulon and Wasps will only finish behind Ulster if they both lose. Presuming that Toulon will beat Bath and top the group, Leinster could do their Irish counterparts a huge favour by beating Wasps and allowing Ulster surpass them.

So, to sum it up: Ulster must beat Oyonnax with a bonus point to give themselves a chance of qualifying. That on its own could be enough but most likely they will still need two results to go their way.

Presuming Ospreys and Toulon both win and top their pools, Ulster will need two of Wasps, Stade Francais, Clermont Auvergne or Northampton to lose or draw in order for them to overtake both sides and get a best runner-up spot.

If you’re still struggling to work it here is the table of all 11 teams still in with a chance of making the quarter-finals.