This match is a critical game for Dortmund because currently, they need four points to reach Bayern Munich and they played one game less than Bayern Munich. If Dortmund loses this game they won't have much chance to win the title at the end of this season but they scored the first goal just after the game start in less than 10 minutes.
Dortumd already fighting back to keep make sure it doesn't go easy for Bayern if they will win the Bundesliga. Bayern were ruthless today and it may have been an effect of the team selection from Tuchel that had some fresh players start like Noussair Mazraoui. Bayern need to take him seriously because he is a really good player that other clubs must have noticed and will come for him if Bayern do not value him. Dortmund are now two goals ahead and the game has not even gotten to thirty minutes. It may also be a goal festival for Dortmund.