Manchester United boss Jose Mourinho's tense exchange with Paul Pogba at Wednesday's training was sparked by a social media post by the player.
Mourinho was left unhappy by what Paul Pogba posted on Instagram during his side's defeat to Derby in the Carabao Cup.
The Frenchman watched the tie from the stands alongside team-mates Andreas Pereira and Luke Shaw.
At one point, Pogba filmed himself and his pals joking and laughing.
Sky Sports reports it was this that left Mourinho unhappy and during training on Wednesday Mourinho turned to United's press officer, John Allen, and asked: "When did Paul post that Instagram?"
Presumably Mourinho was trying to ascertain whether the midfielder posted the clip when United were winning or losing.