Jurgen Klopp said his team are "like idiots" after falling back into the relegation zone - but backed his Borussia Dortmund side to return after the six-week winter break and improve.
Dortmund continued their horrible season with a 10th defeat in the league to bottom of the table Werder Bremen, losing 2-1.
Davie Selke scored one goal and set up another for Bremen to climb off the bottom and leave Dortmund just one spot off the bottom in the Bundesliga.
Rock bottom Freiburg could send Dortmund bottom if they beat Hannover at home on Sunday. Whatever happens, Dortmund will occupy a relegation place at the season's midway stage for the first time, with this game their last before a six-week winter break.
"I wouldn't write us off. We made too many mistakes and now we're there like idiots in the relegation zone. But we're not as bad as that. We have time now to recharge the batteries. We'll correct what we've messed up," Klopp told Sky television.
After being wished a happy Christmas and a better New Year, Klopp replied: "Thank you, it couldn't get much worse."
The 19-year-old Selke opened the scoring with a fine finish in the third minute, easily eluding Manchester United target Mats Hummels before crossing for Fin Bartels to make it 2-0 in the second-half.
Hummels atoned, somewhat, with a heading in Ilkay Gundogan's corner but Dortmund couldn't find an equaliser.
The visitors were poor in the first half, appearing unsettled by Bremen's well-organised defense and counter-attack. Dortmund had to wait 30 minutes for their first effort on goal, and really only threatened through Oliver Kirch just before the break.
Klopp introduced Shinji Kagawa for the second half, but the Japan midfielder was unable to change the game. After setting up Bartels for Bremen's second, Selke should have made it 3-0 before Hummels pulled one back.
Kagawa missed a good chance to equalise with 10 minutes to play, while Bartels struck the post and Clemens Fritz fired over at the other end in a frenetic finale.
"We're all been thinking about it: 'What's the problem? Where's the issue?' We were better at home in the last weeks, but away, not at all," Hummels said.
Dortmund next play on 31 January.
Additional reporting from APReuse content