Relegation-threatened Borussia Moenchengladbach conceded a late goal in their 1-0 loss to Mainz in the Bundesliga on Saturday.
Lucien Favre's men are two points from the relegation play-off spot, conceding an 87th minute goal at Mainz to deepen their troubles.
Andre Schuerrle struck from 25 yards past an outstretched Marc Andre ter Stegen to extend Mainz-s lead on fifth spot to five points.
It was the 20-year-old's 13th goal of the season, equalling the best return for the club, which was set by Mohamed Zidan during the 2006/07 season.
The visitors' task of getting anything out of the game was made difficult when striker Mike Hanke was sent off after picking up a second yellow card in the 53rd minute.
It was a disappointing result for Moenchengladbach after their 5-1 thrashing of Cologne last weekend.
The win ended a four-game winless run for Mainz and put them within five points of the Champions League qualification spot, although Hannover will have the chance to restore the buffer with a trip to Hamburg on Sunday.