I think our biggest problem is mental actually. Sure we have a couple of players in the squad who are not good enough and I don't mean to suggest otherwise. But that's not the main problem.
For some reason, we lack confidence and show a complete lack of composure unless we are facing a team we know are much worse than we are. So we can beat the bottom half teams for fun, and yet against tougher opposition, we are coming up short. It's been like this for more than a season now.
It's not about how the better sides play, either. Yes clearly they punish our mistakes more, but the big difference is not them, it's us. Last night was not unusual, it just highlighted it. But we are the same against Liverpool and Arsenal every time we play them away. Look at our record at Anfield and compare it to Chelsea's. We bottle it every season.
Fortunately, we have the best coach in the world and he will fix this, but it will take time and some new leadership in the side.