A lively cup tie had to wait until the second half for a goal but Hannover took the lead through Martin Harnik’s strike to give them hope of an upset.
However Frankfurt quickly struck back through Taleb Tawatha and Haris Seferovic, before having Hradecky to thank in the dying embers of the match.
Just the three changes each
After victories against Kickers Offenbach and Fortuna Düsseldorf in the previous rounds, this was Hannover’s first chance to test themselves against Bundesliga opposition since their relegation nine months ago.
They were coming off the back of a shock 4-1 defeat to SpVgg Greuther Fürth at the weekend though. They made three changes from that game, with Philipp Tschauner, Stefan Strandberg and Uffe Bech replaced by Samuel Sahin-Radinger, Noah Joel Sarenren Baze and the fit-again Manuel Schmiedebach.
Frankfurt are flying high in the Bundesliga, sitting third after back-to-back victories against Schalke 04 and SV Darmstadt 98. They had needed penalties against both 1. FC Magdeburg and FC Ingolstadt 04 though to get to the third round of the Pokal.
They too made three changes from their weekend starting line-up. Michael Hector, Max Besuschkow and Seferovic all came in for Jesús Vallejo, Mijat Gacinovic and Branimir Hrgota.
Neither side break deadlock in entertaining first half
Frankfurt had more than enough chances to put themselves firmly in control in the first twenty minutes, without actually taking any. Seferovic couldn’t direct an early shot in, but Ante Rebic picked it up, only to smash into the crossbar.
Bastian Oczipka had two chances both go wide, whilst Sahin-Radinger got to a cross before Serferovic after a mistake from Salif Sané. Frankfurt talisman Alexander Meier also came close, but a vital late tackle from Oliver Sorg allowed Sahin-Radinger to kick the ball clear.
Hannover had been kept quiet by the guests, but as Frankfurt’s threat lessened, they grew into the game. Their first genuine chance to score came on the half-hour mark, with Kenan Karaman played through by Harnik. Hradecky did well though to send his shot away from goal.
Edgar Prib also blew a great chance to put the hosts ahead. Connecting with Karaman’s cross, he failed to keep his shot on target, instead firing well over the bar.
Frankfurt respond after Harnik opener
Seferovic missed a golden opportunity to finally give Frankfurt the lead soon after the break. A cross from half-time substitute Tawatha left Sahin-Radinger beaten but the ball was a little too far ahead of an out-stretched Seferovic to put in. With the goal completely open, he would have been kicking himself.
Even more so when Hannover took the lead. A good ball from Karaman found the youngster Sarenren Bazee. He went down in the box under pressure from a defender, but Harnik pounced on the loose ball and with struck in, with a slightly touch off Hredecky.
That fired up Frankfurt and they were soon level. Timothy Chandler whipped the ball into the box after a one-two with Seferovic, and Tawatha at the far post headed it in before an on-rushing Sahin-Radinger could cut him off. It was the Israeli’s first goal for the club.
Four minutes later and the Eagles had completed the turnaround. Prib made the fatal mistake of heading the ball straight at Seferovic, and not even he could mess up the chance presented to him.
Hradecky the hero in dramatic final stages
Hannover had one golden chance to equalise in normal time. A back-heel from Artur Sobiech found Niclas Füllkrug, but an excellent save from Hradecky kept his shot out.
The drama was only just beginning to unfold. A foul by Omar Mascarell on Sané trigged a melee involving most of the outfield players, with the Frankfurt man and Füllkrug booked as a result. Prib could only put the resulting free-kick over.
Another set piece came and went for Hannover, but then Mascarell recklessly stuck a leg out at Sobiech in the Frankfurt box, and to the anger of the visitors the referee pointed to the spot.
Sané had the chance to send the game into extra time, however he was to be denied. Hradecky guessed the right way and kept his penalty out, with the whistle blowing for full-time just moments afterwards to confirm Frankfurt’s passage to the quarter-finals.