Arsenal could be forgiven for reflexively letting their guard down whenever they touch down in Athens. This is not a happy hunting ground for Arsène Wenger's team, although it usually counts for very little. It almost comes as a shock that, this time around, the stakes could barely be higher: failure to meet an exacting set of requirements when they walk out to face Olympiakos in a pulsating Karaiskakis Stadium on Wednesday evening will see them exit the Champions League at the group stage for the first time in 16 years.
The tension surrounding this fixture is at odds with the fact that it has become one of the competition's quirkier rites of passage.