Despite losing Sead Kolasinac to an early injury, Schalke looked solid at the back, and were forcing Hannover to unsuccessfully try their luck from distance.
Zieler was forced into action once again before the break to push Klaas Jan Huntelaar's powerful effort wide of the post.
Huntelaar's luck changed just two minutes into the second half when he broke the deadlock by reaching the front post to hammer home a cross from Eric Choupo-Moting.
Joel Matip should have doubled Schalke's lead when he found himself unchallenged in the box, but the defender somehow managed to head over from less than six yards out.
Hannover were left thanking Zieler again as the Schalke onslaught continued, with Julian Draxler being the latest player to be left frustrated when his curled effort was tipped wide.
The visiting supporters were even more shocked in the 70th minute when Joselu took full advantage of the space offered to him by finding the bottom corner with a powerful effort from 25 yards.
Hannover defended their slim advantage impressively, and held off a late challenge from the Schalke attack to secure all three points.