The photo was shared by @clinicalkaion on Twitter, with Mount watching on as Romelu Lukaku attacked a cross.
“Mount is fixing his hair while a cross is put into the box,” the tweet read.
More than 2,000 retweets later and suddenly, fans were on to something.
Mount’s hair fixation
Type in ‘Mount hair’ on Twitter and you’ll see a wave of tweets highlighting the 23-year-old’s habit.
“Why doesn’t Mason Mount just wear a headband instead of playing with his hair every 2 seconds…,” one tweet reads.
Another says: “Mason Mount I challenge you to go 3 seconds without touching your hair, level impossible!”
There’s now plenty more evidence of it happening, with one fan even creating a 16-second video of various instances of Mount’s hair flicks.
“Completely obsessed with his hair,” an agitated fan wrote in response. “Our future captain is gonna wear our armband completely obsessed with fixing his hair while we lose control of games.
“At least he looks pretty tho right. Cut this sh*t out!”
Mount was at it vs Real Madrid
A Twitter account called @MountOut10 that is unquestionably anti-Mount – the account’s description reads: ‘We will bring you facts, stats and videos exposing the biggest fraud in Chelsea history’ – might have shared the most damning clip of all.
It’s from the Real Madrid defeat, and Mount stops to sort his hair while action is being played out just yards in front of him.
Why are fans upset?
Of course, nobody cares what Mount does if Chelsea are winning. And they have done for so long under Thomas Tuchel.
It becomes more of an issue among fans, though, after successive defeats to Brentford and Real Madrid.
It’s something for them to get upset about, apparently as if it’s evidence that he’s more focused on his hair than actually trying to win.
That’s not true, of course, but in an age of social media, it’s the reality Mount has to deal with.