Martin Harnik's penalty and Salif Sané's header ensured a share of the points, in a game filled with chances and controversy.
Following their hard-fought 2-1 win over Dynamo Dresden last weekend, Daniel Stendel made three changes to the side that started in Saxony. Waldemar Anton, Edgar Prib and Noah Joel Sarenen Bazee were dropped out as Fynn Arkenberg, Miiko Albornoz and Kenan Karaman started in their place.
As for Arminia, they were coming into the game after a last-minute equaliser secured a point at home against FC St. Pauli. The massive effort called for alterations, and Jürgen Kramny responded with three. Christopher Nöthe, Christoph Hemlein and Kevin Staude replaced Andreas Voglsammer, Sören Brandy and Florian Hartherz.
Hannover were keen to keep the HDI-Arena in high spirits with over 35,000 fans in attendance. The away end was also packed and they all drew a sharp, collective intake of breath as Manuel Schmiedebach raced forward from the start and shot into the side-netting.
The hosts were on top from the get-go but found it hard to break down a stubborn and determined Bielefeld back-line. Kramny's side were strong in the tackle and keen to stay compact, meaning Hannover's attempts to make their way through the middle were repelled.
Despite dominating and looking comfortable in the game, it would be Stendel's men who would fall behind. Christopher Nöthe had the awareness to spot the run of Hemlein at the back post. The decision to include them was fully justified as a wicked deflection saw his effort loop up and over Philipp Tschauner and into the back of the net.
That joy would prove to be short-lived and just seven minutes later, pressure eventually led to the leveller for Hannover. It was Kenan Karaman who was upended in the area and, although slightly soft, Felix Brych pointed to the penalty spot. Harnik stepped up and kept his cool to send Wolfgang Hesl the wrong way.
There would be a third goal in the second minute of added time, which was an even more curious decision than the first penalty Brych had awarded. Salif Sané was adjudged to have tripped Kevin Staude. Hannover stood in disbelief while Bielefeld were also a tad shocked, though Fabian Klos tucked away the spot-kick was real calm.
Sané secures a share of the spoils
The second half began in similar fashion to the first as Hannover threw everything at their visitors. Schmiedebach was again involved early on and a lovely move saw him break down the right. His cross was flicked goal-ward by Iver Fossum yet Hesl stood firm to deny him not once but twice from close range at the near post.
Bielefeld were resigned to set-pieces for the following phase of the game, with Hannover in full flight in order to get an equaliser. It would come just before the hour mark when substitute, Sebastian Maier whipped in a corner to the near post. Sané had been seeking redemption and got it with a bullet header that crashed in off the post.
With the scores level for a third time there would be no immediate response from either, instead chances for both at both ends. Albornoz went close for Hannover but was kept out by Hesl. Andreas Voglsammer was denied a superb turn-and-finish for a hand-ball in the build-up before his cut-back was missed by Staude at the back post.
The latter stages saw Bielefeld take the game by the scruff of the neck and push forward for a winner. Nothe wasted a glorious opportunity when through on goal, with his attempted chip ending up in the stands. Manuel Junglas came closer, with his drive from Klos' lay-off ending up drilled into Tschauner's feet for a routine stop.
Four minutes of added time brought no further chances as the game ended level. Hannover are just a point clear of 1. FC Union Berlin and Arminia moved up to 15th ahead of the weekend's other fixtures.