As embarrassing moments go, missing an open goal in the Old Firm Derby is up there with calling your teacher 'mum'.
So spare a thought for Patrick Roberts, who could have marked his first ever appearance in the fixture with a goal but instead will wish the ground could open up and swallow him.
Roberts, on loan at Celtic from Manchester City, just needed to slot into an empty net from barely six yards out after Leigh Griffiths' shot came back off the post.
A formality, you'd think. But big game tensions can do strange things to people.
https://twitter.com/MCFClnfo/status/721664275954188288
Had Roberts scored, it would have brought the teams level at 1-1.
Given everything surrounding the game, only the second meeting between Rangers and Celtic since 2012, the Bhoys' twitter account was impressively calm about the whole situation.
https://twitter.com/celticfc/status/721662826666962944
Others, though, weren't quite so relaxed.
https://twitter.com/MerlyMerlz/status/721665582022729728
https://twitter.com/grahamruthven/status/721663457398034432
https://twitter.com/Choikles/status/721666092465307649
https://twitter.com/Graham_Swann/status/721665557171412993
https://twitter.com/ScottWalkero9/status/721665145936703488
