Niclas Füllkrug scored the only goal of the game in just the eighth minute, and the away side really threatened an equaliser.
Hannover remain third, with Eintracht Braunschweig remaining ahead of them on goal difference.
Hannover looking to keep pressure on leaders
Hannover came into the game six points being leaders VfB Stuttgart, after their dramatic win at 1. FC Nürnberg, and level with Eintracht Braunschweig and 1. FC Union Berlin, with their Lower Saxony rivals Braunschweig ahead of them on goal difference.
They had been held by Erzgebirge Aue in their last game, however André Breitenreiter had three wins from his first five games in charge. He made just one change to his starting line-up, with Felix Klaus replacing Sebastian Maier.
Defeat to FC St. Pauli last weekend had left Düsseldorf dangerously close to the relegation zone, after a run of form that has seen them pick up just two wins since the turn of the year.
They had to make four changes to their starting line-up. Kevin Akpoguma was of course out after his horrific neck injury whilst three more were suspended. Gökhan Gül made his first Düsseldorf appearance from the start, with Robin Bormuth, Alexander Madlung and Marcel Sobottka also coming in.
Füllkrug gives Hannover early lead
It took just eight minutes for Hannover to strike as they looked to close the gap on Stuttgart. Miiko Albornoz and Edgar Prib combined on the left-hand side, with Füllkurg rushing in to connect with Prib’s cross to put the ball past Michael Rensing.
Oliver Fink had already hit the roof of the net for Düsseldorf when they fell behind, and Ihlas Bebou came close to getting an equaliser ten minutes later. Christian Gartner found him with an excellent ball from up the field, but from an angle he could only shoot wide.
Chances for further goals were at a premium after that. Albornoz, who was getting down the left wing often, had a couple of attempts saved by Rensing, whilst Özkan Yildirim had two opportunities go wide for the away side.
Neither side able to add to the goals
Hannover began to ramp up the pressure after the break. Waldemar Anton put a shot wide after some good play from his team, before Martin Harnik saw a header deflect out for a corner. Klaus came close soon after too, but he was blocked in the box before he could pull the trigger.
It was virtually one way traffic, and Rensing was being kept busy. He palmed away an attempt from Klaus, before two chances in little over a minute. First Anton had a shot well saved by the Düsseldorf goalkeeper, and eventually from the following corner he grabbed onto a shot from Klaus.
In the end they couldn’t find the elusive second goal that would have given them the edge on goal difference over Braunschweig. Düsseldorf barely came close either, and they now find themselves just two points above the dreaded bottom three - a flat and worrying display from Friedhelm Funkel's men.