Togolese striker Peniel Mlapa had given the visitors the lead in the first half, but it was cancelled out by Sebastian Polter after a defensive mix-up.
Steven Skrzybski then scored the winner for Union with ten minutes remaining to take his personal tally for the season to seven.
Union replace Quaner with Polter
Jens Keller’s Union side finished an impressive first half of the season in fifth place, four points off the top three. Bochum however were six points and six places further back in eleventh after an inconsistent display in the Hinrunde.
There was a big blow over the winter break in the loss of top scorer Collin Quaner to Huddersfield Town, however Polter has arrived from Queen’s Park Rangers, having previously been on loan with the club, and he replaced him in the starting line-up.
Michael Parensen coming in for the suspended Stephan Fürstner was the only other change from their 1-1 draw with SpVgg Greuther Fürth before Christmas.
Bochum’s only January signing has been Vitaly Janelt joining on loan from RB Leipzig, but he wasn’t in the matchday squad. Patrick Fabian and Felix Bastians came in for Jan Gyamerah and Timo Perthel, the latter of whom was sent off in the 1-1 draw against FC St. Pauli in their most recent match.
Mlapa scores despite home dominance
The hosts started the brighter, applying plenty of pressure on Bochum without creating any clear cut chances. It was in fact their guests with the first notable chance on goal, with Mlapa winning a duel with Kristian Pedersen before his shot was saved by Jakob Busk.
There were then chances at both ends, with a Felix Kroos free kick running straight through to Manuel Riemann, before Johannes Wurtz capitalised on a poor chest-down by Skrzybski only to have his shot saved by Busk.
Union were getting forward more still, but the chances came and went, with a Polter through ball too quick for Skrzybski, and then the newcomer found himself forced wide by Fabian after getting into a promising position.
It would be Bochum though that would take the lead five minutes before the break. Marco Stiepermann’s cross was headed on by Nils Quaschner to Mlapa, whose own header went in via an unfortunate Parensen, leaving Busk helpless.
The hots had a superb chance to equalise almost straight after, with Christopher Trimmel finding Simon Hedlung, but his header was well over the bar. Meanwhile a Stiepermann free kick caused Union’s defence a few problems before being taken by Busk, who also saved another header from Mlapa in first half stoppage time.
Polter and Skrzybski turn game around
The Berliners again started the second half on top, without being able to make it count. Numerous crosses were easily dealt with by Reimann. One he didn’t get presented their best chance in these stages, with Kroos’s ball in headed goalwards by Polter. It would drop kindly for the Bochum goalkeeper though.
They brought on Philipp Hosiner as they looked for the equaliser, but they weren’t counting on a Bochum calamity to hand it to them within 60 seconds of the change.
A Pedersen long ball unlocked Polter, with Bastians slipping in pursuit and his keeper Riemann rushing out of his goal. Polter knocked the ball past him, and had an empty net to aim at for his first goal back with the club.
Neither side created any real chances until Union took the lead with ten minutes remaining. Reimann tried to punch away a free-kick that took a deflection off his own player, but his clearance only went to Kroos, who set up Skrzybski to fire in what would prove to be the winner.
The result moves them up to fourth for the time being, although it could have been more emphatic, but a vital Bastians interception denied Kenny Prince Redondo, who then in stoppage time struck over the bar.