We were going to have a bad day sooner or later. The slow start can be forgiven after Wednesday and wouldn't have been a disaster without the silly soft goal. Then we had a spell where we were quite good leading up to half time.
My main concern would be the second half and our tactical set up. We didn't put a single constructive attacking move together in the seconf half. Instead our players were just running towards the Arsenal goal and trying to run through Arsenal in the process. Time and time again.
We were too open in the middle due to our silly diamond formation (which we for some completely baffling reason reverted back to after half time), so whenever we lost the ball, which was all the time due to our complete lack of composure, Arsenal could just knock it straight up to their forwards with absolutely no obstruction. The second half was an absolute mess.
Players having an off day isn't so alarming, but losing their heads and abandoning any attempt at team play in favour of sheer panic is a bit of a concern. Persisting with a formation and tactical set up that isn't working, even after you had to change it during the first half, due to it not working, is just plain bizarre. You set up a team to play to its strengths...we are starting to get back into a habit of doing the opposite.