They could have even been quite ahead of Bayern Munich in the standings. But things are still going fine for Dortmund now. Of course it wasn't good for them to lose to Bayern Munich recently but their performance was really bad at defending. There was no way they were going to get any point in that match. Dortmund will still hope for Bayern Munich to make a mistake at some point. Bayern Munich are focused on the Champions League also. If they even get bad results then maybe it can affect them in a bad way mentally.
After Dortmund lost the game against Chelsea and lost the Champions League, now Bayern Mucni as the first team on the table lost the game against another team in the premier league these two teams are not in the same situation and both are just racing the or Bundesliga title ut since Bayern Munich had a bad day against Manchester City in champions leag which can have a negative effect on them I see more chance for Dortmund in this season.
Even though it will definitely be difficult for Leg 2 with a margin of 3 goals there but still the chance is still there so for now it would be very funny if they gave up halfway, at least even if they couldn't in the end they still had to try until the end.