I think this will be the case. This was also the case in the PSG match played in Paris, and Dortmund passed the elimination thanks to the posts. PSG had too many balls returning from the post. If something similar happens for Real Madrid, why shouldn't Dortmund beat them? Borussia Dortmund is strong enough to play at the top level. I'm sure Terzic will manage to adapt his students in the best possible way. Also, as a coach, I am sure that he will take charge of bigger teams in the coming years.
This is why I'm always of the opinion that in football anything can happen and as such so no team shouldn't be seen to be too sure is most definitely going to win any game because things as this can happen and the tem may loose not because they weren't playing well but because of the uncertainties that arises which is beyond their control and will deny them of the victory in the game which would have gotten them to the next stage of the game
Dortmund may get lucky and it may get to shock almost everyone who will be witnessing the game that day so I wouldn't want to underestimate Dortmund as they aren't really a bad team such that if opportunities come their way they wouldn't be ab to really get to utilize it to their advantage, Madrid is a team that I know will be definitely not want to make any mistake and will be careful enough to making sure they are able to get pass this stage with the victory they need to be able to get the trophy as aswell maintain their records in the champions league which they have had over a long time where they have not lost a single champion league finals.
So much have been said about the finals between Madrid and Dortmund which has already raised so much expectations and probably pressure on the team which may actually have an effect on their performance so I personally think it's better they just be allowed to perform in their best and eventually what ever the results is the best team goes home with the trophy.