We have made it ridiculously easy for pratically every 'big' team we've played- our losses have been a combination of poor errors by players, being susceptible to losing the ball when pressed high up the field, not having enough defensive numbers to counteract quick counter attacks by opponents etc, having little attacking threat. All of which demonstrate the naviety in which we have approached the 'big' games.
The problem I have is that we haven't learnt from these mistakes, instead we continue to make the same errors time and time again, which is also a example of how we are always reactive rather than proactive.
You only have to look at Mourinho playing Luiz in midfield, as a double pivot in every 'big' game to see the difference between how we have lined up in these type of games, in comparison with our rivals.