Jürgen Klopp was disappointed with Borussia Dortmund's 2-1 defeat to Köln on Saturday.
"We played a style of football that made no sense whatsoever. We were very sloppy in our passing in the first half and made some simple mistakes. This cannot be happening," Klopp said.
"We made things hard for ourselves again. We weren't good enough at the decisive moments, both in defence and in attack. We lacked focus at the back and weren't clinical enough going forward. That's why we still only have seven points.
"We simply didn't do enough against this opponent. We have to turn this situation around. We have to iron out the mistakes. Not tomorrow or the day after tomorrow, but right now.
"We nearly always score and we wouldn't be in this situation if we didn't concede so many goals."