I was actually impressed with the performance borussia Dortmund did put up in the battle against Bayern Munich in the yesterday's fixture as this is like you did stated once in a very long time victory for them because they have not been able to record such victory in a very long time against Bayern Munich and generally this season Bayern Munich hasn't been consistent so they seem to be loosing a few games.
If borussia is able to keep up with a few more wins, they will soon get to the third position on the table as they currently are at the fourth. Dortmund isn't a team thst is characterized with weakness but they have been unable to gain victory over Bayern Munich in a very long time and it has actually been broken after yesterday's game and than I see that Dortmund has in their last five matches lost only one game and has won all other four which is also similar to Bayern Munich, for me that's some show of strength from Dortmund a d so they weren't to be seen as weak.
If Bayern Munich had won they would have been at 63 points which means they would be ten points away from Bayer Leverkusen but then since they lost, they are currently at 60 points which keeps them 13 points away from Leverkusen so it's not out of place if their coach is accepting the fact that they may not be able to win the league title this season because the gap is to much a gap to be able to really meet up.
That is both a success from Dortmund, but they shouldn't be claiming all the victory for their own success, because it was also due to Bayern being terrible too. Bayern lost to Leverkusen 3-0 just recently, would you believe that if you heard it before this season?
This season Bayern has been quite terrible and Dortmund took advantage of that situation. Don't get me wrong, I am not saying Dortmund did something easy, Bayern is Bayern and even on their worst season they are second place, so it is not an easy achievement to beat them. But if you are going to beat them, this season seems to be the one. Last season was almost like that, if Dortmund won the last game they would have been the eventual champions, so Bayern has been not good for a while.