Frankfurt were back in it on 13 minutes when Martin Lanig grabbed the equaliser with a close-range finish, but Pander's dangerous free kick once again caused havoc inside the opposition defence, and Lars Stindl got the faintest of touches to make it 2-1 seven minutes later.
Didier Ya Konan then did well to stay onside to slot home after good work from Andreasen just before the half-hour mark.
Hannover spurned two glorious chances in the second half when Andreasen struck the post minutes after the restart, before Szabolz Huszti hit the bar on 52 minutes.
However it was Manuel Schmiedebach who came closest, when his header was judged to have been cleared off line despite replays showing it to have crossed.
Substitute Alexander Meier gave his team hope when he flung himself at a cross to head home on 68 minutes, minutes after Lanig flashed an effort of his own wide of the goal.
As the home side searched for an equaliser, the game became fraught, with both teams having several chances, and the best of those was wasted by Hannover who couldn't find the net despite a six-on-three attack towards the end.