A night to forget for so many reasons but one to be remembered for Alexis Sanchez's wonder goal.
It was marred by shameful scenes as Cologne fans went on the rampage both inside and outside of the Emirates and for so long it seemed to be going so wrong for Arsenal.
But the second half fight back and Sanchez’s goal changed the mood completely and at least it spared Arsenal the embarrassment of losing the first game in a competition they do not really want to be in.
Arsenal boss Arsene Wenger said: “In the second half he came alive. He is still running to fight and come back to his best physically.
“But Sanchez is Sanchez and even if not back physically he is an exceptional footballer and can deliver the decisive pass or goal. He scored and can always create something special.”
Let’s be honest, the Europa League has become almost a nuisance for Wenger and just another game, another hurdle to trip up Arsenal, another stick for the fans to beat him with.
Sure enough, they started badly, went behind and got booed off at half time when it was all in danger of going horribly wrong for Arsenal.
But the second half fight back showed there is some spirit - the tone set by half time substitute Sead Kolasinac - within a team which too often looks in danger of drifting towards mediocrity.
There probably is not much pride to be taken from a night ruined by the Cologne fans and no-one should excuse their behaviour by dressing it up as passion and a great advert for German football. It wasn’t.
They are also, at best, a pretty average team playing their first European game for 25 years and that just about sums up the changing of the guard in North London.
Tottenham beat Borussia Dortmund in the Champions League one night and 24 hours later Arsenal fall behind to Cologne in the Europa League. Sadly for Arsenal, they have fallen a long way.
And a bad night threatened to get even worse when Cologne went ahead after yet another David Ospina clanger. His poor clearance was an invitation for Cologne striker Jhon Cordoba to smash a dipping 45 yard shot which sailed over the stranded keeper’s head.
Arsenal struggled to get back into the game, they looked disjointed and a real mess. On top of that, poor Rob Holding was struggling badly in defence as Bittercourt had the beating of him down Arsenal’s right.
Not surprisingly, Arsenal were booed off at half time and Wenger responded by substituting Holding for Kolasinac. The Bosnian defender went to left back, Arsenal switched to a flat back four and finally the tide began to turn.
Theo Walcott chased down a ball in the 50th minute, his cross was deflected off Lukas Klunter and the ball fell to Kolasinac and he smashed a brilliant left foot volley into the far corner.
If only Arsenal had 11 Kolasinacs in the team then they would not lack heart. But at least it fired them up for an impressive fight back.
Arsenal went ahead after 67 minutes when Sanchez scored with a goal of the highest quality. Alex Iwobi’s long ball forward left Sanchez with a lot to do, he chased it down and then turned Cologne defender Jorge Mere inside out.
Sanchez then cut inside and, from a seemingly impossible angle, curled a stunning 20 yard right foot shot into the far corner. It was a world class goal.
That got a wonderful reception and shortly afterwards Jack Wilshere came on as a 68th minute substitute to a fantastic ovation as he made his first appearance at the Emirates since May 2016.
Arsenal completed the turn around after 82 minutes when Walcott’s shot was charged down and Bellerin then slid home the rebound.