Champions League permutations: What do Arsenal and Liverpool need to do to qualify?

Your guide to the possible ramifications of tonight's Champions League clashes

Arsenal and Liverpool go into tonight's Champions League clashes with qualification hanging in the balance. For Arsenal, only a win against Borussia Dortmund will guarantee their progression from the group stages before their final fixtures.

Liverpool face the bizarre situation where beating Ludogorets tonight may not be enough to secure a place in the knock out round, but they may still progress (mathematically) if they lose. Here is your guide to all the possible permutations of tonight's fixtures...

If Arsenal beat Borussia Dortmund...

Then Arsene Wenger's team qualify for the knockout stages. They can then top the group if they beat Galatasary in a fortnight and Dortmund lose to Anderlecht. If the German side draws in Belgium but Arsenal win in Turkey, it will go down to a head-to-head between them and the Gunners.

If Arsenal draw with Borussia Dortmund...

Then they will still qualify if Anderlecht fail to win against Galatasaray tonight. If the Belgians win tonight, then a point in Istanbul will be enough to send the Gunners through in second place.

If Arsenal lose to Borussia Dortmund...

Then they will still qualify if Anderlecht and Galatasaray draw. If Anderlecht win, then the Belgians will still have to beat Borussia Dortmund and hope Arsenal slip up in Istanbul. If Galatasaray beat Anderlecht, they will still have to beat the Gunners to take qualification to a head-to-head.

Steven Gerrard (left) was rested against Real Madrid, but is set to return to Champions League action for Liverpool tonight (Getty images) (GETTY IMAGES)

If Liverpool beat Ludogorets...

And Real Madrid draw with or beat Basel, then Brendan Rodgers's side will still have to beat the Swiss outfit in two weeks to ensure qualification. If Basel beat the European champions, then Liverpool will have to win their final match by more than one goal to go through in a head-to-head.

If Liverpool draw with Ludogorets...

And Basel lose tonight, then Liverpool will still qualify with a win in Switzerland. If Basel draw, then the Reds will have to win by at least one goal when the teams meet to progress. A Basel win tonight would send Liverpool out.

If Liverpool lose to Ludogorets...

Then they can still qualify, mathematically, as long as Ludogorets only win 1-0 and Basel lose to Real. Even if this happens, the Reds would have to beat the Swiss outfit by at least four goals to clinch an unlikely qualification. However, all of this will be irrelevant if Ludogorets can avoid defeat at the Bernabeu in their final fixture.