We will definitely finish top of our Europa League group - but our unbeaten record in the competition has gone.
A second-half penalty condemned us to defeat, but Red Star Belgrade’s draw with BATE Borisov means we can’t be caught by them or Cologne.
The German side’s winner was not without controversy as Sehrou Guirassy went down inside the box with Mathieu Debuchy in close attention.
The referee deemed it worthy of a penalty and Guirassy picked himself up to slam the spot-kick past David Ospina.
It was very much against the run of play. Indeed, one early save apart, Ospina had next to nothing to do.
At the other end we probed for openings, but were denied by dogged defending and flawed final balls on an uneven surface.
Francis Coquelin got as close as he’s ever been to a first Arsenal goal with a shot that thudded off the base of the post, and the Frenchman also forced Timo Horn into a sharp save.
Mohamed Elneny and Ainsley Maitland-Niles combined neatly to play in Jack Wilshere. But he was challenged just as he looked to apply the finishing touch.
Guirassy’s penalty gave Cologne something to cling onto and they defended even more gamely after that.
Horn saved Per Mertesacker’s header and Wilshere’s rasping drive, and Arsene Wenger threw on Reiss Nelson and Eddie Nketiah in a bid to save the game.
Nelson almost did the trick after a mazy run through the home side’s defence. But this was Cologne’s night.
HOW IT HAPPENED
WHAT IT MEANS
This defeat is not a damaging one. We’ve already qualified for the knockout stage of the Europa League and will definitely finish top of Group H. We have 10 points while Cologne and Red Star each have six.
Our final game in Group H of the Europa League is at home to BATE Borisov on Thursday, December 7.
But next up it’s Burnley in the Premier League, at Turf Moor on Sunday.
Danny Welbeck made his first start for us since October 14 - more than five weeks ago. These were his best moments before he made way for Alex Iwobi at half-time.
5 - Welbeck’s pace almost takes him beyond the Cologne back three but a defender sticks out a boot to nick the ball away
19 - Debuchy overlaps and Welbeck peels off at the back post. The cross eludes the Cologne defence but Welbeck can’t get the ball under control
27 - A delicious drag-back takes Welbeck away from his marker but his pass to Wilshere is cut out
33 - So close to a fine goal. Welbeck finds space outside the corner of the box and curls a shot just beyond the far post
35 - Coquelin’s through-ball puts Welbeck through on the left, but Giroud can’t quite reach his cross
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