In the heart of Germany's sooty industrial past Arsenal ground out a victory that offered the north London club a tantalising glimpse of a bright future - a win in the Champions League against an at-times intoxicating Borussia Dortmund side that ranks as one of the club's finest away performances,either on home soil or in any corner of a foreign field.
It would be easy to underestimate the magnitude of their achievement in front of a passionately ferocious, then stunned and meek Westfalenstadion; to reduce it down a hardy defensive display and an opportunistic strike.
Only Bayern Munich have beaten Dortmund there in European competition since 2011. Indeed they are the first English team to sneak out of this remarkable arena with all three points in their pocket.
It wasn't the bewilderingly quick, coherent interplay in attack that has been regularly spotted around N5 and further afield this campaign that was the foundation of a victory which significantly eases the pressure on Arsenal's hopes of emerging from their fiendishly difficult Champions League group.
No, instead it was something more intangible that saw them right.
Qualities like resolve and discipline aren't readily attached to Arsene Wenger's band of fleet-footed pixies but that is what they displayed last night as they stared down and smashed through the yellow wall before fending off any of the home side's attempts to level things up after Aaron Ramsey's 62nd minute opener. Up went the red blockade, and it wasn't to be defeated.
This was an astounding win, one to make the previously despondent and frothing Arsenal faithful chuckle with disbelief.
But what does this mean in the wider sense? It is of course difficult to take a victory in difficult circumstances where one team were able to get a result that doesn't typify their style of play and then extrapolate it out across the length of a season.
What is undeniable though is that this was the type of game that highlights inherent qualities of Arsenal that will undoubtedly stand them in good stead for the remainder of the campaign.
They were assured when Dortmund poured forward and shelled their 18-yard box; after Ramsey's bravely taken goal they grew in stature - a sure sign of a young team starting to believe that this a stage which they belong on. Before then they were resolute at the back, especially when the home side threatened to overrun them.
If the question is 'are Arsenal title contenders?' then based on the evidence so far the only answer is yes. Rather than be broken by their tough run of fixtures they seem to be warming to the task - victories against an in-form Liverpool side as well as Borussia Dortmund mean they go into a game against Manchester United, whisper it quietly, as favourites.
The caveat of that is the defeat against Chelsea and the reverse against Dortmund last month, the argument being that Arsenal are flat-track bullies.
There is no denying they were left exasperated by the quality of Chelsea's second string and while they put up a good fight at the Emirates, were winded by a sucker punch from Jurgen Klopp's men.
Those defeats may show a potential weakness against the big boys but let it not be said that this means they aren't title contenders; they play eight games against their top four rivals and another 30 against the rest of the league.
It may sound flippant but win those and you'll be doing alright. Of course this is an exaggeration but winning the league is about consistent highs, not peaks and troughs - something this Arsenal side seem to be mastering.
Plenty have been hasty to try and put a stop to the Arsenal title bandwagon in recent days but on this form it will take a brave man to bet against them.
A team like Dortmund are not easily vanquished, especially not at home. One by one, the reasons for doubting their credentials are slowly disappearing into the night sky.
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