Pogba was one of a number of players who failed to perform as United scrambled to claim a point in a 2-2 draw with Southampton at St Mary's, having been 2-0 down inside 20 minutes.
Now, it seems the playmaker bore the brunt of the Portuguese anger, with the aforementioned source claiming that Mourinho gaving his star man a huge dressing down in the dressing room.
"You don't play. You don't respect players and supporters. And you kill the mentality of the good honest people around you," he is alleged to have said.
A raft of injuries mean Pogba was brought back into the fold in the middle of the park, having been made to do with a place on the bench for the narrow victory over Young Boys in the Champions League in midweek.
Mourinho bemoaned the lack of pressing from certain members of his midfield following Saturday's draw, but having singled Scott McTominay and Nemanja Matic out for praise, it appears his comments were firmly aimed in Pogba's direction.
"We lost so many balls in midfield, that was difficult to have that continuity," Mourinho fumed. "In the second half we went back to that dynamic where we lost too many balls in midfield, when the players don't understand that simplicity is genius.
"The second goal was a direct free-kick and the first goal is because we don’t press the ball when our block is low. We don’t have many mad dogs – the ones that bite the ball and press all the time.
"McTominay and Matic did a very good job for two midfield players."
The latest clash is just one of a number incidents between the pair, with Pogba having previously been told he would never captain the club again due to his behaviour.