- Jhon Córdoba nets stunning goal from 40 yards.
- Sead Kolasinac equalises four minutes after half time.
- Alexis Sanchez puts the Gunners ahead for the first time.
- Hector Bellerin extends lead with eight minutes left.
- Kick-off delayed by 60 minutes due to crowd safety.
- Thousands of Cologne fans enter home areas of The Emirates Stadium.
- Ticketless Cologne supporters reportedly stormed a barrier and attempted to enter the stadium.
- Four people arrested for public order offences.
Well that is all we have time for on what has been quite a night at The Emirates. The attention now turns to Uefa and what action they could now take against both Arsenal and Cologne after an organisational calamity. But until next time, it's a very goodnight.
Full time: Arsenal 3-1 FC Cologne
On an eventful night, Arsenal hold on and get the points which ensures they start their Europa League campaign on a winning note. Jhon Cordoba had threatened to cause a shock but goals from Sead Kolasinac, Alexis Sanchez and Hector Bellerin completed the comeback in the second half. The less said about the Gunners' display the better however, they were distinctly average in a first half in which Cologne more than held their own.
Reiss Nelson on for his debut, replacing Theo Walcott for the last seven minutes. Fair to saw the England man was woeful tonight.
GOAL! Arsenal 3-1 FC Cologne (Hector Bellerin)
Arsenal secure the points via a nicely worked third goal. Kolasinac's cross comes through to Walcott, who is denied by Horn but on the follow-up Hector Bellerin arrives on cue to slot into the corner for his first of the season. After a bumpy start, it looks like being all three points for the hosts.
Alexis Sanchez curls home a brilliant second to put Arsenal ahead.
Which comes to nothing. Arsenal have at least temporarily sorted themselves out at the back.
Sanchez tries to repeat the trick from earlier this time from a free-kick, but Horn gets down to it well. The boyhood Arsenal fan has had no chance with either or the goals tonight.
Ospina finally makes a save, keeping out Cordoba as he raced in on goal. Nacho Monreal at fault there. Corner Cologne...
Sead Kolasinac celebrates drawing Arsenal level.
Amid the celebrations, Jack Wilshere has made his Arsenal comeback, replacing Alex Iwobi for the final 20 minutes or so.
GOAL! Arsenal 2-1 FC Cologne (Alexis Sanchez)
Alexis Sanchez back with a bang to put Arsenal ahead for the first time. The Chilean is put away down the left. He is forced wide but cuts back inside and despite being closed down he whips a shot superbly inside the far post, with Horn motionless. Fabulous strike and some way to re-announce yourself to the home faithful on his first start since deadline day.
Chance for Arsenal to take the lead for the first time. Ainsley Maitland-Niles goes through on goal, tries to round Horn but the German cuts the ball out and the opportunity is gone.
Meanwhile, Jack Wilshere is preparing for his first Arsenal appearance for 13 months.
The Cologne fans have stirred again and are bellowing from the away end as they attempt a rare attack. They go again with the substitute Milos Jojic but his strike is saved well by Ospina. An hour gone, and pretty even it must be said.
Better from Arsenal since the break with Cologne barely getting a sniff of the ball. The away support have calmed down a fraction too, until Ospina gets a glimse of the I'd expect.
And right on cue the 'keeper receives a slow pass-back from Monreal ad almost presents the ball straight to Zoller. Look forward to hearing Arsene Wenger defend his display tonight.
GOAL! Arsenal 1-1 FC Cologne (Sead Kolasinac)
The equaliser has hardly been coming but Arsenal are level just after the restart. Theo Walcott breaks in behind but when his control takes him wide, he attempts a cross which is charged down but Kolasinac, with virtually his first touch, takes it first time on the volley and smashes it past Horn.
59,359 'tickets sold' at The Emirates tonight. No information as whom to.
Second half underway.
Teams back out at The Emirates. Sead Kolasinac is coming on for the home side. Rob Holding, who had a bit of a stinker of a first half, is replaced.
Half time: Arsenal 0-1 FC Cologne
Goodness. Quite an evening of football and we're only half way through. Let me bring you up to speed if you're only just joining us, thinking we would have reached full time and be ready for an early night.
The match at The Emirates Stadium was delayed by 60 minutes after crowd trouble in north London. Ticketless Cologne fans are alleged to have attempted to break into the stadium and clashes with police have broken out.
The reality is many of them have succeeded in entering The Emirates having purchased tickets for the Arsenal end of the stadium. The allocation of 3,000 has swelled to at least double that, with fans dotted all around the ground. The atmosphere has been electric.
The game itself has not been short of drama either. Jhon Cordoba netted a superb opener early on after a horrible error from David Ospina. Arsenal have been unable to respond and have been, though perhaps understandably, slow out of the traps.
Cologne have been the story on and off the pitch tonight, and are threatening to leave London with more than just a slap on the wrist from Uefa. I'm off for an orange and a lie down.
Finally some neat interplay in the Cologne defensive third as Sanchez feeds Maitland-Niles, but his cross is easily cleared as Giroud stands and stares. He has been almost anonymous.
Change for Cologne as Jonas Hector - you'll know him from a transfer rumour column or two if not from anywhere else - is replaced by Milos Jojic. Ten minutes until half time.
Cologne threaten again when Ospina spills a cross from the left as Zoller threw himself at the ball. He failed to make contact but the whistle had already gone for an offside. The Costa Rica goalkeeper is in for a roasting in this second half in front of the travelled support.
Cologne fans begin the celebrations as their team takes the lead.
Jhon Córdoba celebrates putting Cologne into a shock lead.
It says a lot about the way teams in England are supported that we're all captivated by the Cologne support and the energy they are putting in to supporting their team.
Meanwhile, one Cologne fan has been ejected from the Arsenal end. It took seven security men to remove him. Not sure that was worth it.
Talking of things that weren't worth bothering about, Theo Walcott has just fired Arsenal's best chance wide. Cologne remain ahead mid-way through the first half.
Possibly among the reasons for the Arsenal ends [which remain] being so empty is down to those supporters who tried to get in but simply gave up. Among those which have persevered in a family of five who have just sat down in front of me, which includes three young children. There may be a great atmosphere inside The Emirates, but there are some victims of what has been at best an organisational mess.