The 21-year-old attacker has claimed the players' efforts are not to blame for the heavy defeat, but a lack of confidence, something the Germany international hopes they can shrug off before their Europa League clash with Metalist Kharkiv on Thursday.
“The mentality of the players is not a problem,” he told bundesliga.de. “Everyone is absolutely motivated – if you saw our training session you would see that. It is just confidence we are lacking. Why? I cannot say.
“After a good [2-0] win against Freiburg, I thought we were on for a positive set of results. We were compact, allowed them very little room, and we played well up front. It is that sort of performance we desperately lacked against Dortmund.
“We were obviously disappointed [with the result]. We had done a lot of work, and wanted to break Dortmund's long run of unbeaten results, but we were poor, and against a team like that you will pay.
“When you don't succeed, you have to rally together, rather than go around with your head down. We have analysed [the performance] and know we have to do better. I am sure we'll show a different side to us soon.”
The former Mainz man then went on to speak about the club's Ukranian opponents in the Europa League.
“So far we have not gone into detail on our opponents,” he said. “That will come this week. But I know the club has money, they have signed some players from South America and will certainly have a good, strong team on the pitch."