Sebastian Polter had given them the lead but things were complicated by the sending off of Roberto Puncec just before half-time.
Würzburg failed to make the most of their extra man, with Damir Keilach doubling the lead late earn to earn his side a fourth win on the bounce. Würzburg remain winless in six.
One change each
The form of these two sides coming into the game could hardly have contrasted more. Union were unbeaten since the winter break, with four wins out of five, whilst Würzburg, after such a promising start to the season, had won just once in ten attempts – the stunning victory over VfB Stuttgart just before Christmas.
The hosts had won 2-0 against 1860 Munich exactly a week earlier, but goalkeeper Jakob Busk picked up a muscle injury in that game that will keep him out for several weeks. Daniel Mesenhöler replacing him was their only change.
Würzburg made only one change as well from their 1-1 draw with SpVgg Greuther Fürth. Clemens Schoppenhauer replacing Felix Müller.
The now departed Collin Quaner, whose place in the side has been seamlessly taken over by Polter, scored the only goal when the two sides met in Würzburg earlier in the season.
Polter bullet header the difference at the break
Würzburg had to soak up plenty of pressure in the early stages, with Steven Skrzybski having a shot deflected after skilfully beating Schoppenhauer, whilst Christopher Trimmel and Toni Leistner had chances from corners. Würzburg did pose a threat in their limited number of attacks though, with the best chance falling to Sebastian Ernst, which was saved by Mesenhöler.
Kreilach then came close for Union, going wide from a Simon Hedlund cross, but they would eventually lead. Felix Kroos’s corner was headed on by Michael Parensen, and Polter met it with his own head to score a third goal in six games since re-joining die Eisern from Queen’s Park Rangers.
Union looked firmly in control, but Würzburg had chances for an equaliser when Elia Soriano headed wide a Rico Benatelli free-kick and Tobias Schröck was just off target after being found by Ernst.
The big turning point came just before half-time. Puncec, who had already been booked for swinging his arm into Sorinao, came together with the Würzburg striker again, giving away another foul and seeing his second yellow.
With a man advantage they almost made immediate use of it, with Rico Benatelli setting up Emanuel Taffertshofer with the resulting free-kick, and it needed an excellent save from Mesenhöler to keep out his shot from the edge of the box.
Kreilach settles it after backs-to-the-wall effort
The game inevitably opened up in the second half, with Würzburg seeing a lot more of the ball, without being able to craft any genuine opportunities on goal. It was a much scrappier affair though too, with plenty of challenges flying in from both sides.
Union’s best chances were coming from set pieces. One Kroos free-kick was blocked by the Würzburg wall, moments after Robert Wulnikowski had felt the need to angrily get them into formation. Another free-kick from further out required the keeper to punch the ball away.
They were doing excellent at the back though, and Würzburg just weren’t testing Mesenhöler enough, with Schoppenhauer resorting to a shot from closer to the centre circle than the penalty area.
Union on the other hand needed just one opportunity to put the game to bed. A long ball was headed on by Polter to Kreilach, who got the better of a grounded Wulnikowski to strike in from a tight angle.
Marco Königs had a late chance saved by Mesenhöler, whilst at the other end Kreilach nearly had another, just shooting wide of the mark. So up to second they went, at least until Hannover play Karlsruher SC on Saturday afternoon.