Southgate has inadvertently fuelled Maguire's humiliation - opinion
England had been two goals up and cruising, but the Tartan Army still sensed they could mount a comeback in the friendly at a rocking Hampden Park.
They hadn't come close to threatening their old rivals - failing to have a single shot in the first half - but the mood shifted upon Maguire's introduction.
He was mocked and taunted by the Scotland fans whenever he was in possession of the ball and at points brought out sarcastic celebrations after each successful pass.
They continued to chip away at him and a breaking point on a challenging night was reached when he turned an Andy Robertson cross into his own net to reduce Scotland's deficit to one.
It was an unfortunate moment but one that will go down as poor defending from a player that really should not have been on the field at that moment in time.
England would go on to win the game over their old rivals 3-1, but the result has only left more questions regarding Maguire's involvement in the England fold.
The 30-year-old's place with the Three Lions has been under scrutiny for a while - especially now considering he has played more international minutes than domestic this season.
However, he seemingly has a lot of wiggle room under Gareth Southgate, who has leaned on him quite prominently for England at the last three major tournaments.
Southgate's loyalty to him became even more evident after the match when he leapt to a staunch defence in which he labelled his treatment "a joke".
"From a Scotland fan's point of view I get it," he said. "I have no absolutely no complaints with what they did. It is a consequence of ridiculous treatment of him for a long period of time, frankly, and I think our fans recognised: 'OK, there might be a bit of heat from our own supporters but we are not going to have it from others getting into him.'
"But it is a joke. I have never known a player to be treated the way he is. Not from the Scottish fans – by our own commentators, pundits, whatever it is, they have created something that is beyond anything I have ever seen."
While it is good to see a manager look to protect his player, this latest episode could have easily been avoided if Southgate looked past his loyalty, which is inadvertently inviting more issues onto Maguire's doorstep.
Did he specifically need to come on in place of Marc Guehi? Given it was a friendly, would it not have been an option to give Fikayo Tomori some minutes or hand 20-year-old Levi Colwill his England debut?
Instead, Southgate opted to launch Maguire - a player already desperately short of confidence - into the lion's den, where he endured a draining mental barrage lasting around 50 minutes.
A similar event occurred the weekend before last when he was sarcastically cheered onto the pitch by Arsenal fans before his Manchester United side went on to lose the game late on.
The Gunners identified Maguire as a weak spot and Scotland did exactly the same but on a more fierce level.
Unfortunately, there is every chance something like this will happen again and Southgate needs to be more aware of that going forward - particularly when it comes to his future squad selections.
This incident will have only raised the argument that he should be picking the squad based on merit over previous performances and with the next international break in a month's time, there could now be even more pressure on Maguire to turn things around at club level.