Borussia Dortmund moved top of the Bundesliga by thrashing Cologne, who suffered the German top-flight’s worst start since the 1962-63 season.
Cologne have lost all four Bundesliga matches this campaign, have only scored one league goal and have a goal difference of minus 11.
Both Pierre-Emerick Aubameyang and Maximilian Philipp netted twice, with Sokratis Papastathopoulos also scoring.
Cologne’s Europa League game at Arsenal on Thursday was delayed by an hour.
About 20,000 Cologne fans arrived in London for the first match in the group stage despite a ticket allocation of only 2,900, with the Gunners going on to win 3-1.
Dortmund have won three and drew one of their four Bundesliga matches, but did lose 3-1 to Tottenham in the Champions League on Wednesday.