Arsenal or Barcelona: Which club has bigger issues at present?

It was a chastening midweek for two of Europe's biggest clubs, as Arsenal and Barcelona both suffered humiliating defeats in the first leg of the Champions League round of 16. Inevitably, talk of crisis has followed for both, but which side has greater problems?
On the face of it, both Arsenal and Barcelona have plenty to play for this season. The Gunners are fourth in the Premier League, two points off second, and remain in the FA Cup.
The Blaugrana, meanwhile, sit second in La Liga, one point behind Real Madrid, and are through to the Copa del Rey final.
Plus, for a few more weeks at least, both sides are still in the Champions League.
But the feeling at present is that each club is underachieving and, no matter how the rest of the seasons unfold, changes are needed at both the Emirates Stadium and Camp Nou.