I feel bad for Dortmund's fans.
Dortmund take the first position in Group F among PSG, Newcastle and Milan, people said they're lucky.
Dortmund beat PSV, people said they're lucky.
Dortmund beat Atletico Madrid, yet people said they're lucky.
Dortmund beat PSG, once again people said they're lucky.
Now if Dortmund can beat Real Madrid, people will say same, they're lucky.

I would say if it's happen for one or two times, it's correct it might be lucky. But it's already four times, Dortmund really put their effort to win the match.
Yes, it's funny, but in fairness it should be noted that PSV, PSG, Atletico, Milan and Newcastle are either having a terrible season or are not initially clubs that are very difficult to beat in European competition. Considering that Dortmund themselves are in 5th place in the Bundesliga, we can say that so far they are winning the battles of the underdogs.