Arsene Wenger's Arsenal travel to Borussia Dortmund with their Champions League fate still in their hands.
Group F is tightly contested with the Gunners vying with Dortmund and Napoli for a place in the knockout stages and all three teams gaining six point from their first three games.
This sets up a tantalising clash between the Premier League leaders and Juergen Klopp's men on Wednesday, with the winner gaining a very sizeable advantage going into the last two games.
So without further ado, here are the three key tactical decisions which could determine the outcome of this clash of two European heavyweights.
1. Who will be Arsenal's midfield men?
The midfield worked extremely well against Liverpool, with Arteta recording a staggering 99 successful passes, leading to a 94% pass completion rate.
Ramsey also got forward well and provided the decisive moment of the match, but can the pair stand up to Dortmund's frightening range of attacking talent?
2. Blaszczykowski or Aubameyang?
Polish winger Jakub Blasczcykowski is a fan favourite at the Wesfalenstadion, but with Pierre-Emerick Aubameyang starting most of their Bundesliga games, will Klopp elect for the Gabon international for Arsenal's visit?
Blasczcykowski was picked in the reverse fixture at the Emirates due to his propensity for performing in the big games, but the right-winger failed to make much of an impact and could be dropped for Wednesday's match.
Either way, Kieran Gibbs will be in for a tough evening patrolling the left flank for Arsenal.
3. Tomas Rosicky?
Arsene Wenger has a selection headache waiting for him at right wing, with Tomas Rosicky deputising for the Gunners against Liverpool in place of the injured Theo Walcott and Serge Gnabry.
The Czech Republic star gave a very competent display, linking with his fellow midfielders effectively and stretching the play when possible. Against Liverpool, Arsenal's number seven completed 57 of his passes, with a pass accuracy of 85%.
But Rosicky was up against a woeful Aly Cissokho on Saturday, can he repeat the trick against a much more experienced and reliable Marcel Schmelzer?