Rafael van der Vaart has urged his Hamburg team-mates to ask themselves some tough questions after defeat to Eintracht Frankfurt kept the club joint bottom of the Bundesliga.
Van der Vaart, 29, set up both Hamburg's goals as they lost 3-2 to Eintracht Frankfurt on his second debut for the club, but called going two goals down after only 20 minutes "embarrassing" and a nightmare".
He warned that a similar start against back-to-back title winners Dortmund next weekend could be disastrous. Speaking after the match, the Netherlands international said: "We have to look in the mirror and ask ourselves if every single player, and we as a team, have gone to the max.
"Maybe we were running scared, but we definitely lacked self-confidence."
Hamburg remain in a state of turbulence, with director of football Frank Arnesen facing criticism and coach Thorsten Fink in desperate need of getting points on the board.
Fink told Die Welt: "Of course I was really annoyed [by the defeat], but it's positive how we reacted. It is a different team to a few weeks ago."
Dortmund, Borussia Mönchengladbach and surprise package Hannover 96 are next up for Hamburg, and Fink said: "The champions arrive in the nick of time. We are outsiders and have nothing left to lose."
The coach added that he had taken encouragement from Van der Vaart's contribution, explaining: "He had a good match. He talked a lot on the pitch and worked the defence. I am very pleased with his debut. It also shows he can handle the pressure."
Arnesen said he still believed Hamburg could turn the season around, telling Morgenpost: "Since Rafa's arrival, we have progressed in every way."