Ciro Immobile and Pierre-Emerick Aubameyang struck either side of half-time and the German club would have been more emphatic victors than 2-0 but for the reflexes of Wojciech Szczesny and their own wastefulness.

For the second time in two matches Danny Welbeck illustrated why his finishing is considered below par for a top forward by failing to convert a one-on-one with a goalkeeper.

With the match goalless and Arsenal under relentless attack, Welbeck managed to drag Aaron Ramsey’s clever pass wide with just Roman Weidenfeller to beat.

It was a key moment and the £16million signing from Manchester United, who had other chances to open his Gunners account, only enhanced concerns over his record in front of goal.

Had he scored it would have been a grave injustice, however, given that Arsenal’s back four were tormented throughout in a display that will see Arsene Wenger face renewed criticism for refusing to sign defensive reinforcements over the summer.

At times they were comically poor with Laurent Koscielny and Per Mertesacker fully culpable, although they were offered little protection by Mikel Arteta, who was also exposed by the quick wits of Dortmund.

And in front of Arteta, Mesut Ozil once again drifted around aimlessly, contributing nothing until his second-half withdrawal.