A well-worked Sercan Sararer goal gave the hosts an early advantage, but they failed to keep their visitors down and couldn't capitalise with their further chances.
Even then, it wasn't until Simon Terodde leveled that things went downhill. Thomas Eisfeld added another and Janik Haberer rounded off the scoring.
Fortuna slightly fortunate to be ahead at the break
Bochum, similarly to their weekend win, began well and imposed themselves on the game straight away. Marco Terrazzino's cushioned header gave Thomas Eisfeld the chance to score his second in as many games, but his shot came off the post. Another good chance fell to the former-BVB midfielder soon after, as a lovely counter-attack put him one-on-one with Michael Rensing; this time, his shot was off target.
The hosts did respond and it was the influential Kerim Demirbay at the heart of everything good. Sercan Sararer first fired a shot wide of Manuel Riemann's goal before the Bochum stopper was twice called into action by Demirbay from range. It wasn't long before Fortuna went ahead, however, and they scored in style. Ilhas Bebou burst to the by-line before cutting the ball back towards the penalty spot, where Sararer swept home from 12 yards and left Riemann with no chance.
Both sides continued to come forward but without much luck. Onur Bulut and Simon Terodde both had chances to bring Bochum level on the right but were denied by Rensing, who did well to keep out Eisfeld's attempt to dribble round him moments before. Michael Fink fired a few warning shots for his side, but they were largely limited to efforts from range due to their Ruhr neighbour's defensive efforts.
Bochum turn things around
The start to the second half was nothing like the first, with Fortuna enjoying a dominant spell. Demirbay again went close with a free-kick, while Lukas Schmitz shot narrowly past the post from just over 20 yards. Gertjan Verbeek had to respond and did, bringing Janik Haberer on for Tim Hoogland.
While Haberer didn't have a direct part to play, his arrival seemed to spark Bochum into life. A stunning run from Marco Terrazzino saw him set up Bulut, but his shot was blocked by the legs of Rensing. That mattered little, however, when Terodde managed to stay on side and poke home the rebound; parity was restored.
Seemingly shell-shocked, the hosts conceded another soon after. There was nothing Rensing could do this time, as Eisfeld arrowed a free-kick from over 20 yards into the top corner. The ball kissed the post on the way in, sparking wild celebrations in the visiting end. Verbeek was keen to calm things down, though.
Their joy almost turned to despair from kick-off, as Fortuna found Bebou free on the right with space to run in to. Unfortunately he couldn't find the finish to match the move, and his effort went wide. When it seemed like things couldn't get any worse, they did. A floated free-kick from Eisfeld from Haberer in the box, who rose highest to pick out the far corner and compound Fortuna's misery in a stunning 10 minute spell.
The hosts couldn't find a way back into the game, and Benjamin Cortus' whistle signaled the end of an entertaining game. Bochum outlined that they are a real contender in the promotion race after previous attempts had fallen away throughout the season, as they rose to fourth. Fortuna, by virtue of other results, now sit just three points above the relegation play-off zone.