Yaya Sanogo left the field with an apparent hamstring injury.
A memorable night for Yaya Sanogo ended on a disappointing note for him personally.
The French under-21 international scored in only the second minute of the game against Borussia Dortmund, his first ever competitive strike for the Gunners.
Sanogo signalled to the bench his need to be withdrawn late in the game, walking gingerly off the field, with Arsenal's medical staff looking worriedly towards the bench.
He was holding his hamstring, an injury which could put him out between anything from three to six weeks if serious.
Sanogo has a history of injuries, but if anything this one was likely picked up due to his lack of regular competitive football.
The striker, who signed on a free transfer from Auxerre last summer, had only ever scored in a pre-season friendly, when he bagged four against Benfica in the Emirates Cup.
Sanogo was in the team due to unavailability of Danny Welbeck and Olivier Giroud, through injury and clerical reasons, with Lukas Podolski taking his place.