Borussia Dortmund sporting director Michael Zorc has warned coach Lucien Favre the club's situation is "more than unsatisfactory" and demanded improvements against Barcelona on Wednesday.
Dortmund are struggling for results in the Bundesliga and a 3-3 draw at home against bottom club Paderborn on Friday left them with just two wins from their last eight league matches.
The Champions League has provided welcome respite for Favre's men this season and they sit second in Group F, just one point behind Barcelona.
Victory at Camp Nou would ease pressure building on the coach's position.
While there has been no explicit suggestion of a change in coach at Signal Iduna Park, Zorc made it clear the board are concerned.
"Obviously the topic will be discussed publicly because our situation is more than unsatisfactory," Zorc told Funke Sport.
"Of course we will analyse that very intensively. But we are going to the match in Barcelona with Lucien Favre and we expect to see a significant increase in performance there.
"We need a performance. We finally need a good performance on the pitch so you can look forward."
Dortmund CEO Hans-Joachim Watzke also chose to speak out after the Paderborn result, reassuring Favre he still has the club's backing.
However, he made it clear the team's current form would not be allowed to continue without consequences.
"Dear Lucien, you still have our trust," Watzke said at the club's AGM. "But in the end football is always defined by results.
"We all hope you and the team are able to turn this around. You have all the support we can give you."
Directing a stern message towards the club's players, he added: "Pull yourselves together and play like it is expected from Borussia Dortmund. You as a team must know that only words are not enough.
"It is your duty to let them be followed by actions."