The win will give them some confidence and belief in the race for Champions League qualification. It was also their third consecutive win in the league.
Although the German giants won 2-0, they could have easily scored more goals, and the scoreline probably flatters Union Berlin.
The home side were quite dominant from start to finish, and they thoroughly deserved the three points.
Dortmund had plenty of chances to increase their advantage after the goal from Marco Reus, but they were poor with their finishing. They will have to address that in order to finish the season strongly. If they keep missing quality chances, eventually, they will be punished against a better team.
Raphael Guerreiro scored the second goal of the game on the 88th minute to send Dortmund up to 5th in the league table, just four points adrift of Eintracht Frankfurt fourth place.
The only chance Union Berlin managed to create was when Emre Can gave the ball away in a dangerous area, and Berlin hit the crossbar from the resulting move.
A night to forget for Erling Haaland.
The Borussia Dortmund striker worked hard throughout the game, but it wasn’t his night.
Not only did he miss the penalty (which was turned in by Reus on the rebound), his movement was quite mediocre as well.
Usually, Haaland is lethal with his finishing, but he did not manage to get on the score sheet tonight despite his side creating loads of chances.
Jadon Sancho was unplayable.
The English winger was brought on with 30 minutes left to play, and he was undoubtedly the best player on the pitch. Union Berlin struggled to live with his pace and flair.
He also set up the second goal of the game for Dortmund.