The Manchester United loanee was adjudged to have blocked a Nico Elvedi header with his hand by Scottish referee Willie Collum.

Sounds fair enough, right?

Well, it would have been if the ball hadn't smashed Smalling flush in the face.

The reaction to the decision was, as you'd expect, polar opposite from the two sides:

We've all had those moments watching football when we've seen a replay of an incident and thought, "Eh!?!"

Monchengladbach's Twitter admin certainly experienced it tonight...

Hats off to Monchengladbach though, at least they had the decency to apologise after Lars Stindl smashed home the penalty to snatch just their second point of the campaign against the group leaders...

How soon is too soon? The German side gave it just three minutes before cracking out this meme.

Shortly after the full-time whistle Smalling expressed his disappointment at the decision.

Roma later revealed on the club's official Twitter account that the match officials had admitted their mistake, and accepted their apology with good grace: "The #ASRoma post-match management spoke to match officials, who admitted they had made a mistake in awarding the penalty. We respect them and thank them for being honest. Now head to the next game #ForzaRoma."

Why didn't VAR intervene?

Wondering why the decision wasn't overturned by VAR?

The technology isn't available until the final in the Europa League.

We wonder what referee Collum would have given for the technology to be available tonight?

Earlier in the year, he came out in support of VAR saying "there's no referee in the world who wouldn't support VAR".