Peter Bosz claims his side's poor first half was the reason behind Borussia Dortmund's 3-2 defeat against RB Leipzig.
It is Dortmund's first defeat in the Bundesliga this season, as Leipzig ended Dortmund's dominance at home, who were beaten for the first time in 41 games at the Westfalenstadion in the league, stretching back to Jurgen Klopp's tenure.
Despite his side remaining top of the Bundesliga, their lead has been cut to two points, with Bosz frustrated about how the game went.
Speaking post-match, Bosz said to the Bundesliga: "It wasn't a great game.
"There were a lot of tackles and it was very tense but we didn't play proper football, especially in the first half. We had a lot of difficulty with Leipzig's pressing and didn't do well before the break."
Bosz had hoped that the second half introductions of Julian Weigl and Christian Pulisic would give Dortmund more impetus to go for the victory, although things didn't go to plan.
He continued, stating: "We wanted to change things in the second half but unfortunately we conceded a third goal straight away and had a man sent off. That made things very difficult after that."
Dortmund and Leipzig now turn their attention to crucial Champions League ties this week. BVB face APOEL Nicosia this Tuesday, looking to gain their first points in the group, while Leipzig host FC Porto on Wednesday, looking to improve on their solitary point amassed in their debut in the competition.