Borussia Dortmund coach Thomas Tuchel says too many "technical errors" cost his side in their late 1-0 defeat to RB Leipzig.
In the first Bundesliga game played at Red Bull Arena, the hosts won their maiden top-flight match thanks to Naby Keita's 89th-minute goal.
And Tuchel admitted he never felt Dortmund had control of the game, with their mistakes ultimately proving costly.
"It was obvious that we made too many unforced errors in defence and in the central midfield area," he told the media.
"There were many technical errors and a lack of concentration. Since we were very defective that meant that we never had the feeling of being dominant."
Tuchel also rued his side's missed opportunities, having managed only one shot on target before Andre Schurrle struck the crossbar late on.
"We had enough half chances to create some clear chances, to take the lead and to win the game also," he added.
"We did not manage to do it, and, at the end, we then conceded a goal that had not been expected."