Gundogan injury mars Dortmund preparations
The midfielder only returned from a back injury late in 2014, so Jurgen Klopp will be hoping it is not a serious setback.
The visitors had to come from behind in the match at the Esprit Arena after Joel Pohjanpalo gave Dusseldorf the lead, with Jakub Blaszczykowski converting a late penalty.
Dortmund were grateful to Roman Weidenfeller early on as he made two good saves, but there was nothing he could do with four minutes of the half remaining.
Charlison Benschop cut the ball back for Pohjanpalo to poke home and give the hosts a surprise lead.
Klopp introduced Ciro Immobile at the break and he almost brought the visitors level with a low shot across goal.
Dortmund began to pose a greater threat with Mats Hummels heading over and Immobile seeing an effort rebound off the post, with Michael Rensing beaten.
They were saved with nine minutes to go as Blaszczykowski was brought down by Jonathan Tah in the area, the Polish midfielder duly scoring from the spot.
Dusseldorf still had a chance to win the game as Axel Bellinghausen found space in the penalty area, but he failed to connect properly and the ball drifted wide.
Dortmund return to league action on January 31 against Bayer Leverkusen as their attentions revert back to a scrap for Bundesliga survival.