Arsenal's first dropoff of the season may come back to bite them.
After drawing 1-1 with Southampton in the league on Sunday, the Gunners weren't able to raise their levels in the Europa League and suffered a second loss of the campaign with a disappointing 2-0 away loss to PSV Eindhoven.
Qualification to the next round of the competition had already been confirmed, but Mikel Arteta knows that not finishing top could become a serious block for further progress in the tournament due to a major rule change.
