The Schanzer took an early lead through yet another Moritz Hartmann penalty, but failed to get on in a game dominated by bookings.
Marco Russ found an equaliser with 20 minutes to go and Pascal Groß was given a second yellow not long after.
Despite having a man advantage late on, the Eagles couldn't press home their advantage and missed out on a vital win.
Hartmann holds his nerve
Things began badly for the hosts, as a long ball forward from Ramazan Özcan caught the Frankfurt defence off guard. Hartmann and David Abraham went head to head, with the ball catching the latter's hand. Sascha Stegemann correctly pointed to the spot, with Hartmann squeezing the ball past Lukas Hradecky's out-stretched hand.
It was a half of few chances, but the opportunities that did arise were glorious. Szabolcs Huszti whipped in a great ball to the back post for Marc Stendera, although he was denied by Özcan's leg. Hartmann could have added a second when Benjamin Hübner played him in with a long ball, but his chip looped over the bar.
There were further chances before the half, as Haris Seferovic sent a half volley wide of the mark but not before Stefan Lex was denied by Hradecky; Ingolstadt led at the break.
Russ rescues a point
Aside from Luca Waldschmidt's massive missed header, Ingolstadt were the side in control. Hradecky made another important stop to deny Hartmann, and produced an even better save to keep out Romain Brégerie's headed effort. Marvin Matip found himself in the unlikely position of just outside the six-yard box, but fired inches wide of the mark.
Then, against the run of play, Frankfurt equalised. A corner was taken short and played into Marco Fabian, the Mexican picked out Russ and he headed past the stranded Özcan to the delight of the home faithful. Abraham and Waldschmidt had excellent chances to win the game after Groß got sent off; however, they couldn't convert and the game ended, fairly, all square.