On Sunday afternoon the 2. Bundesliga provided an intriguing match-up as two of the division's on-form sides faced off.
A solitary strike from the league's most in-form player, Bobby Wood, helped Union to overcome Heidenheim.
The side travelling to Berlin this Sunday looking to end Union's three game unbeaten run was the impressive Heidenheim; the team from Baden-Württemberg suffered just one league loss in 2016 and went into the game on a five-game unbeaten streak.
The first opportunity of the game came from the hosts. An early free-kick saw Felix Kroos play a short pass to Christopher Quiring, the midfielder delivered a ball into the area where it was headed across to Bobby Wood. Unfortunately he couldn't get much on his header and Jan Zimmermann collected comfortably.
It was an entertaining start to the game as both teams battled well and provided some excellent football, however both were cancelling each other out which meant there was a lack of action for Zimmermann and Jakob Jensen in goal.
Union Berlin once again threatened from a set piece, once more a long range freekick was played into the area. Zimmermann failed to claim the ball in and this allowed Damir Kreilach to try his luck from an acute angle, the Croatian wasn't far off as his shot cannoned off the post.
Wood sends Union ahead
Just before the half hour mark the deadlock was broken, the home side earned a corner and from that corner top goalscorer Wood was allowed plenty of space to head home his 17th goal of the season from close range.
The home team were left angry as the referee didn't award a freekick on the edge of Heidenheim's area and thanks to that the away side hit Union on the counter. A long ball down the left saw a cross to the back post where Marc Schnatterer arrived and sadly for Heidenheim his effort was struck into the ground and bounce just wide of the post.
Following the goal things got heated between the two teams and there were plenty of fouls. Heidenheim were left frustrated time and time again as they struggled to create the chances to get themselves back into the game.
Their chance finally came a couple of minutes from the break, Schnatterer was played through on goal and as he bore down on goal he went down, the midfielder was rushed from behind as Toni Leistner piled the pressure. There was contact on the midfielder, however the referee ruled that Schnatterer went down too easily.
Second half fails to spark
Heidenheim started the better of the two teams in the second half. They came close after Schnatterer tried his luck from a freekick and the thirty year-old was just off the mark as his effort flew wide. Shortly after Marcel Titsch-Rivero played through Robert Leipertz, disappointingly for the away side Jensen was quick off his line to deny him.
Unfortunately for the spectators the standard of football dropped in the second half, the amount of offsides and fouls meant the game was stop-start and neither side could gather momentum.
The two early chances for the away side in the second half were the only decent chances for either side, the quality dropped massively and neither side could muster up chances.
Union Berlin will be delighted with the victory as it now sees them up to 6th place, as for Heidenheim they drop down to 9th place due to Greuther Fürth's victory today. The home side have another tough match next weekend as they travel to face third place Nürnberg. Heidenheim on the other hand have to bounce back with a win against struggler's Paderborn.