After watching this match, I feel that the main reason for Dortmund's defeat is their poor match strategy. Dortmund's tactics were not good in this match. We have seen the performance of Dortmund in the previous matches. They played well. Even against big teams, they win only because of excellent match strategy. But their performance in this match was poor. They dominated the match, attacking a lot. But did not keep their defense strong. In the past matches we have seen Dortmund attack less but their overall gameplay has been stable. But even though Dortmund attacked a lot in this match, their gameplay was not stable.
In attack Dortmund played very well, but in defense they again make mistakes. I will say that Schalke were also good in this match, they were very active and it was obvious that they wanted to level the score with all their might, in the end they succeeded.
Schalke have fallen too low in the table, they need to get out of there, and they have the potential to do so. Bayern are back in the lead, while Union Berlin, which until recently pushed Bayern out of first place, is already 7 points behind Bayern.
I noticed that Union Berlin have very good results when they play only in one tournament, but as soon as games in European cups are added, the results immediately deteriorate, perhaps the players simply do not have time to have a good rest.
I watched Dortmund's performance in the previous few matches against Schalke. Although they attacked very rarely, each of their attacks was organized. And their defense was solid. In the 5 matches prior to this match, Dortmund conceded only 4 goals, while they scored 14. Dortmund would not have dropped points if the defense had been strong against Schalke.
The Schalke team was at the bottom of the points table for a long time. But the performance of this team is very good in recent times. My guess is that Schalke will be able to climb out of the relegation zone in the next few weeks. Schalke is now only 1 point behind Hertha.
Union Berlin should now focus on the Europa League. Berlin has no chance of doing well in the Bundesliga. They have played poorly in their last four matches and are now 7 points behind Bayern Munich.