I would say we lacked some composure in crucial moments. Of course Barça and Chelsea aren't soft opposition but we threw away too many chances. And you defend with 10 men if needed so it won't be a walk in the park.
Btw, who's back for this game? Krul? Haidara? Tiote? Santon?
http://www.physioroom.com/news/english_premier_league/epl_injury_table.php
They reckon Tiote and Santon back. Saying that, our medical team seem to just guess nowadays
Without proper full-backs it'll be a struggle, your wide players are very good.