[...] they are just not ready to become champions so that their self-confidence is not too strong compared to their opponents, that's why they become champions because they have strong self-confidence apart from mental and also quite good abilities in playing.
Dortmund Mentality is not really good to be a champion, same as what happened to Liverpool when facing Real Madrid. I also believe that Mentality and self-confidence is really needed to become a champion. If we are talking about abilities, Dortmund is in real great performance especially in this year, they have done everything to reach UCL final, but i think their performance totally different when facing Real Madrid in Final.
There is no doubt about skill and abilities of Dortmund, we can see what Dortmund done before facing el-Real in the UCL final, i think Dortmund winning all the matches easily even with less conceded goal, but they couldn't show it in the final. Real Madrid players is really ready for the UCL final. So we can conlude that Mentality is really necessary to be a champion.