Florian Kringe's goal midway through the second half was enough for Borussia Dortmund to claim all three points at Cologne on Wednesday night.
Kringe struck the winner in the 65th minute as Dortmund extended their unbeaten run to five matches and moved up to seventh in the table in the process.
Cologne lost their second straight match after three consecutive victories and are now 11th with 13 points.
The game was very quiet in the first half hour with neither team able to do much offensively - Cologne because they didn't have the means and Dortmund because they couldn't breach Christoph Daum's well marshaled back-line.
Nelson Valdez missed two excellent chances around the half-hour mark, however.
His initial header was saved by Cologne keeper Faryd Mondragon and the rebound was blasted against the post by the Paraguay striker.
Dortmund missed another opportunity five minutes later as Jakub Blaszczykowski headed just past the left post.
The visitors continued to press and Kringe struck the crossbar with a header after 57 minutes.
Dortmund finally took the lead eight minutes later.
Tinga sent the ball into the box and Tamas Hajnal re-directed the pass to the left where Kringe had plenty of room to place the ball into the bottom corner.
Cologne attempted to hit back, Milivoje Novakovic's curling free-kick from 18 yards going over the wall but straight into the arms of Dortmund keeper Roman Weidenfeller.
