Hertha Berlin and FC Koln are both seven points clear of the Bundesliga bottom three after playing out a goalless draw at the Olympic Stadium.
The visitors dominated possession in the opening minutes, but it was Hertha who created the first clear opportunity when Sebastian Langkamp tested Timo Horn with a powerful header.
Hertha grew in confidence after that chance, and they threatened again when Per Skjelbred fired just wide of the target midway through the first half.
Thomas Kraft was called into action to keep out Koln before the break when Miso Brecko picked up the ball out wide before beating a couple of defenders and unleashing a low effort.
Despite sharing possession evenly, it was Hertha who looked the most dangerous in the second half as Genki Haraguchi somehow managed to send the ball wide from a few yards out.
Koln finished strongly to test Kraft again when Anthony Ujah was gifted the space to target the top corner late on, but neither side could find a breakthrough in the closing stages.
