What was a tough contest for the majority of the game, which Union led through Sebastian Polter, turned late on when the on-loan Mainz striker and Damir Kreilach scored twice late on to secure a 0-3 win.
Vitus Eicher had to be alert early on in the game, making a good stop from Damir Kreilach's powerful header. He came out to close the angle well on hot-shot forward Sebastian Polter, forcing him to shoot over in an early scare for the hosts.
That was the warning for Lions and they didn't take heed. Christopher Quiring beat his man before drilling a low cross toward the near post. Polter was ready and waiting, deftly flicking the ball past the helpless Eicher and into the net for a deserved opener.
Union were doing their best to add a second, although 1860 were fighting to try and work a way back into the game. Rubin Okotie and Illie Sanchez both had good chances to bring them back on level terms but some committed defending saw their attempts blocked.
Despite the efforts of the home side, Norbert Düwel's men were looking dangerous on the break and Polter's through-ball near handed Maximilian Thiel a tap in, but for some fine defending from Christopher Schindler.
The visitors continued to trouble on the counter and Eicher had to make two impressive saves from Polter early on in the half. Kreilach also had a chance to extend their lead but was again denied by the 1860 stopper.
As the half wore on further chances fell the way of both sides. Daniel Haas was rarely tested, however, while Eicher was under continuing pressure from the Union attack. Guillermo Vallori hit the post from Daniel Adlung's cross, as the search for an equaliser grew ever more desperate.
Any late fight-back was quickly eradicated when both Kreilach and Polter finished off swift, attacking moves to seal a fully deserved 3-0 win for the visitors.