Borussia Dortmund were brought back down to earth on Saturday as they followed up securing a place in the DFB-Pokal final with a goalless draw against Cologne in a Bundesliga clash at Signal Iduna Park.
A 3-2 comeback victory over Bayern Munich in the Pokal semi-final at the Allianz Arena on Wednesday will have raised spirits in the Dortmund camp, but Peter Stoger made it six games against BVB unbeaten as Cologne earned a share of the spoils.
Although failure to win means third-placed Dortmund could be overtaken by Hoffenheim, who entertain Eintracht Frankfurt on Sunday, BVB are guaranteed Champions League qualification as a result of Hertha Berlin's 2-0 defeat at Werder Bremen.
Ousmane Dembele scored one and assisted another in the win at Bayern but was dropped to the bench as one of four changes from Thomas Tuchel, but Dortmund still created enough for a win.
A moment of madness from Marco Reus saw him poke Gonzalo Castro's goal-bound header home from an offside position, while Marcel Schmelzer's shot from the edge of the box looked destined for the net until Cologne goalkeeper Timo Horn got his hand to it.
Dembele was sent on by Tuchel in the second half but, with Cologne content to dig in and hold out for a point, there was no breakthrough, adding greater importance to Dortmund's meeting with Hoffenheim next Saturday.
Pierre-Emerick Aubameyang thought he had given Dortmund the lead when he turned home Shinji Kagawa's cross at the back post in the 14th minute, only to see a flag raised for offside against the Japanese.
Neven Subotic, on loan at Cologne from Dortmund, almost inadvertently found the back of his own net when intercepting Reus' pass for Aubameyang, but Frederik Sorensen spared his blushes with a goal-line clearance.
The hosts continued to control proceedings and Reus fired over from just outside the six-yard box after Aubameyang raced down the left and cut back to the Germany international.
Cologne almost made them rue that missed chance, but a pair of former Dortmund players let them off the hook. Milos Jojic latched onto Artjoms Rudnevs' backheel and dragged wide, before Leonardo Bittencourt scuffed his shot at the end of a scintillating solo run into the box.
Tuchel's team would have gone into half-time ahead had it not been for a lapse in concentration from Reus, who needlessly interfered after Castro beat Horn to the ball to head on target.
Horn was forced into action by Reus within a minute of the restart and the Cologne goalkeeper produced an excellent save to push Schmelzer's 20-yard strike away from the top-left corner.
Tuchel introduced Dembele and Raphael Guerreiro for Reus and Kagawa, and the Frenchman galvanised the ailing Dortmund. His scoop over the defence was cushioned down for Aubameyang by Castro, but that touch was just behind the striker, who shot wide.
Dortmund switched to a back three with Lukasz Piszczek replacing Sokratis Papastathopoulos and Guerreiro was denied a stoppage-time winner as Horn got down to parry his header, with BVB shut out for the first time in the Bundesliga since a goalless draw with Schalke on October 29.