Jurgen Klopp has warned his Borussia Dortmund side that they must get the basics right in order to hit top form.
Dortmund have failed to win in their last two matches and have conceded three goals in both of those games.
Klopp revealed that he has made his defence study extensively in order to correct their problems ahead of this weekend's match against Borussia Monchengladbach.
He told the club's official website: "There are distinct phases in the development of a football team. There´s no chance for development if you are not ready to accept setbacks.
"We showed them all the goals against us in their entire creation. The transitions were actually okay, but one body swerve, and we were those crucial few centimetres off.
"We need to get back to these basic entities, and I think we have tackled this problem."
After an indifferent start to the season Dortmund trail league leaders Bayern Munich by seven points after five matches.