The motivation for Matic’s attack has not been explained.

He was responding to relatively innocuous comments Onana made about Lyon in the build-up to the game, when he said he respected the French club but believed United were “way better”.

However, it is notable how strongly the former Serbia midfielder defended the man Onana replaced, David de Gea, when the Spaniard made his own series of mistakes in May 2019, saying, “He is one of the best goalkeepers in the world and will be for years to come.”

Was Matic using Onana as collateral damage to reinforce a point shared by many that United made a mistake and treated one of their best players of recent times badly when they opted not to renew De Gea’s contract in 2023 and sign the Cameroon international instead, for £47.2m from Inter Milan?

The situation was heightened when Onana, rather than remaining silent or at least waiting until after the game to respond, ignored cautionary advice and hit back, adding: “At least I’ve lifted trophies with the greatest club in the world. Some can’t say the same.”

Matic never won a trophy as a United player.

It was against that backdrop Onana made a catastrophic mistake for Lyon’s opening goal in the 2-2 draw, then erred for the injury-time equaliser, the negativity for that heightened massively by the first inexplicable blunder.

If that performance was an isolated one, it would have been bad enough.

But it is acknowledged even by those closest to the former Ajax and Inter Milan goalkeeper that Onana’s United career has been scarred by a series of big mistakes.

He has eight errors leading to goals in all competitions since he joined United – the most by any Premier League goalkeeper in that time.

A feeling Onana was being scrutinised in a way he hadn’t been previously in his career became evident in his first few weeks at United, when he was chipped from 50 yards in a pre-season friendly against Lens.

Onana had been following instructions to take up a starting position higher up the pitch when his team had the ball, only for Diogo Dalot to give it away under no pressure.

The reaction was intense and the keeper was lampooned in some parts of social media. Even though he wasn’t to blame, his performances became the subject of debate.

It put Onana on the back foot from the first moment.