Referee and VAR controversies had an impact on the match
Although the referee was not the main reason why Borussia Dortmund did not win the match, some of Tobias Stieler's decisions affected the result. Most significantly, the decision to give a penalty against Pascal Groß for his duel with Tim Kleindienst provided an equalising chance for Gladbach.
As Groß pulled the striker's jersey during the corner, it is still a normal practice between footballers during set pieces. It is up to the referee's interpretation to judge if there was enough contact to call a penalty in such a play. As a lack of certainty seemed to be in the air due to the amount of time VAR took to call the referee to the cabin, it is a decision that cost BVB their first away win.
Another controversial moment was when a Gladbach header hit Guirassy's arm inside the box, as the home side called for a penalty early in the game. Two compelling arguments could tend to either side: Guirassy's arm was way too close to his body, but, at the same time, he inevitably stopped a direct shot on target and a clear scoring opportunity.
Despite the short distance to react to the initial header, that non-given penalty is the subject of debate — a debate that will likely take over the roundtable sports shows next week.