Arsenal started their Europa League campaign in Group H with a 3-1 victory against Cologne on Friday.
The match was delayed when over 20,000 supporters of the German Bundelsiga showed up, causing a delay due to overcrowding.
The kickoff was delayed for an hour and four arrests were made for public order offenses after extra police had to be deployed. The sheer volume of away fans around the Emirates prevented home supporters from getting in, although they were eventually able to enter.
Alexis Sanchez celebrates after a goal. /Photo from Sina.com
Alexis Sanchez celebrates after a goal. /Photo from Sina.com
The London Metropolitan Police said extra officers had been sent to the stadium, after scuffles broke out before the opening whistle.
When the match did get underway, Cologne would take the lead in spectacular fashion with Jhon Cordoba lobbing a shot over David Ospina from 40 yards out.
But substitute Sead Kolasinac later equalized with a thumping volley. Then Alexis Sanchez, who nearly left the club to join Manchester City on transfer deadline day, scored a stunning goal, curling it past Timo Horn.
Hector Bellerin then adds a third from close range to complete the Gunners a 3-1 comeback win.