As most neutrals would have expected, Barcelona defeated Arsenal at home to move on to the next stage of the Champion's League. Less than two weeks ago, Arsenal were in the hunt for silverware in four competitions; they are now down to two.
I was unable to watch the match (sometimes classes are so inconvenient), but based on what I have read about it, the Gunners were completely outclassed. Much is being made of the referee's silly decision to send off Robin van Persie, but whether that effected the outcome of the game is at least questionable. Arsenal had only 31% of possession and not a single shot on goal for the entire match - their goal was an own-goal scored by Barca defender Sergio Busquets.
If this defeat has a silver lining it is that Arsenal will have fewer games to play between now and the end of the season, and can focus their attention on the two remaining competitions - the Premier League and the FA Cup - neither of which involves a team anywhere near the caliber of Barcelona. Manchester United, Arsenal's only real obstacle in both competitions, is eminently beatable. It only remains to be seen if this Arsenal side - which on paper and on the field seem little more than a shadow of the "Invicible" team. Who, from the present team, would have competed for a starting spot in that 11? Fabregas is one. Nasri and Wilshire are plausible. But that's about it.
As much as I hate to say it, if Arsenal do not win at least one of the two remaining competitions, it may be time for Wenger to start rebuilding the team (presumably around Jack Wilshire and Samir Nasri).