The Scottish referee was the man in the middle in Rome as Roma went up against the Germans in their third group game.
The Serie A side went into the game with four points and knew a win would help them take control of the group.
And they were heading for that following Nicolo Zaniolo’s opening goal in the first half and a great defensive performance in the second.
But Borussia Monchengladbach eventually got their goal thanks to a late controversial penalty.
Former Manchester United defender Chris Smalling was involved, with Collum deeming his header a handball:
Lars Stindl stepped up to slot home the penalty for the visitors and earn them a point.
But all the post-match discussion will centre around Collum and his performance.