Hannover squandered their chance to go second in the Bundesliga after slipping to a 2-0 away defeat to Cologne on Sunday, while Hamburg picked up a valuable away win against Freiburg.
Mirko Slomka's side took to the pitch at the RheinEnergieStadion knowing that a win would take them to just four points behind league leaders Bayern Munich after nine rounds of matches.
However, the Reds failed in their quest, as Lukas Podolski's brace condemned them to a loss and left them seventh in the standings with 15 points, seven points off the pace.
On the other hand, Cologne are now 10th with 13 points, six points clear of the relegation zone.
The other Bundesliga match on Sunday took place at the Dreisamstadion between struggling sides Freiburg and Hamburg, and it ended in a 2-1 victory for the visitors.
Heung-Min Son gave Hamburg the lead after 12 minutes but Papiss Demba Cisse equalised for the hosts just two minutes into the second half.
HSV restored their lead on 74 minutes when Ivo Ilicevic found the target but could have had to settle for a draw when Freiburg were awarded a penalty with just nine minutes of normal time left.
But Cisse failed to convert his spot-kick, and the match ended in a 2-1 win for HSV, who are now level on seven points with Freiburg in the dropzone.