To be fair, Arsenal deserved to win that game especially after Van Persie's moment of brilliance.
We just don't seem to create enough chances which means we struggle when we go behind. I don't think we've won when we've gone behind this season but to be fair, we attacked better in the second half and Reid was unlucky not to get a goal towards the end but maybe we should have switched to a 4-4-2 a bit earlier.
At the end of the day though, we will have to play better to progress in the FA Cup against a team which will have 5-6 of their best players back into the team.