#5 Defensive frailties will concern Wenger for tougher tasks that lie ahead
The only negative aspect from Arsenal's 4-1 win over CSKA Moscow in the first leg of the Quarter-finals was their vulnerability to quick counter-attacks that seemed to trouble them several times in the game. Ahmed Musa, in particular, caused a few problems simply due to the sudden burst of pace he provided during counter-attacks.
The fascinating fact about Arsenal is that while on the offensive end they are capable of beating any side remaining in the Europa League, if they remain vulnerable from counter-attacks, they will have a hard time keeping the likes of Atletico Madrid and several others quiet, assuming they will have to face each other at some point to be crowned champions in the end.
Taking into consideration performances like these, Wenger seems to have the ability to pull the rabbit out of the hat whenever he is under pressure and victory in this competition in order to earn Arsenal a route back into the Champions League will certainly be on the back of his mind.