Well what you said here is true because looking at what psg displayed at the day of the final it was unexpected and I believe many people were shocked. After psg scored there second goal in that match inter Milan lost all confidence and that was the beginning of there losing. However it is not an easy thing to qualify for champions League final,  inter Milan has quality players but I don't really know what happened if it was over confidence. Depesite that they lost , I believe they have gathered experience that will really help them this season. All they need is just to restratigise there pattern of play.