Hannover soared up the Bundesliga table following a 2-1 victory over Borussia Moenchengladbach on Sunday.
Both sides had chances to open the scoring in the first half but the scorers were not troubled until after half-time when Didier Ya Konan scored in the 57th minute.
Konan's striking partner Mame Biram Diouf added a second goal in the 76th minute.
But Moenchengladbach, who would have gone third with a victory after Schalke were held to a draw by Hoffenheim, got back in the contest just two minutes later.
Norwegian midfielder Havard Nordtveit thumped the ball into the bottom corner of the goal from the edge of the box to make it 2-1.
In Sunday's other match, third-placed Schalke had to come from behind to secure a 1-1 draw away to Hoffenheim.
The home side had the better of the first half and took a deserved lead when Sejad Saliovic scored a penalty after 30 minutes.
But Schalke stepped up a gear after half-time and rightfully earned a draw when Klaas-Jan Huntelaar also scored from the spot with 10 minutes left.
