On the field, it ended up being a straight forward night for the Gunners as three second half goals ended the German’s hopes of a famous win in north London after they'd gone in ahead at half-time.
However, there was plenty to discuss off the pitch as well with Koln fans delaying the kick-off and taking over parts of the Emirates Stadium, resulting in some scuffles.
Officials were forced to put the kick-off of the Group H opener back an hour due to the huge number of travelling fans with an estimated 20,000 making the trip.
Having turned up at the Emirates Stadium, many without tickets, Uefa and Arsenal took the decision to delay the game over safety fears.
Koln’s large travelling contingent were given a moment to saviour just 10 minutes in when big summer signing Jhon Cordoba scored a stunning strike from 35 yards after a mistake by Arsenal goalkeeper David Ospina.
Ospina's clearance did not have enough distance on it and Cordoba had the foresight to see the goalkeeper off his line before he brilliantly lifted it over the Colombian.
The Gunners toiled as they tried to get back in to the game and rarely threatened the visitor’s backline.
Their best chance of the half came when Alex Iwobi played in Theo Walcott but under pressure, the winger dragged his shot across the face of goal.
However, whatever was said at half-time worked wonders for Arsenal as they levelled four minutes after the restart.
Sead Kolasinac, on as a substitute at half-time, scored his second for Arsenal since joining in the summer, levelling matters with a great volley from just inside the box after Koln failed to clear a Walcott cross.
Having got on top of Koln, the home went ahead thanks to Alexis Sanchez in the 67th minute, the Chilean scoring a fine solo goal, cutting in from the left before bending a wonderful striker beyond Timo Horn.
The Gunners killed off the contest eight minutes from full-time, a fine flowing move resulting in the ball coming to Walcott, who saw his effort saved before Hector Bellerin slide in to convert the rebound.