Tullberg did the basics well, but his mistakes cost the result
Mike Tullberg said previously in his pre-match press conference that: "the players haven’t forgotten how to play football." And he was right.
Football should be more straightforward than what Dortmund was attempting to do, and Tullberg should get credit for doing the basics. By playing two electric wingers like Gittens and Adeyemi, BVB always offered a goal threat to a slow-paced Bremen defensive line. Pascal Groß, positioned as a pivot 6, also provided reasonable control for Dortmund in possession.
However, when Tullberg stopped doing the basics, that when things started to go downhill. Having a 2-nil lead with a wholly improvised backline following Nico's red card was fortunate enough, but he took too long to reestablish a balanced defensive system. Sabitzer, out of position as the pivot, should have covered Bittencourt's shot on goal, while Groß was poor as a right-back at the beginning of Bremen's second goal.
Only after the draw did Tullberg decide to put Anton in. Still, it was too late. With both Gittens and Adeyemi leaving at the same time earlier in the second half, BVB did not offer much threat to Bremen besides that set-piece pandemonium saved by Zetterer.
Indeed, he was put in a difficult position and still has little experience as a manager in professional football. But, as much as he deserves credit for what credit is due, his choices were key to the final result.