“I think everyone saw his [Mourinho’s] frustration was showed in the situation where it should be a free-kick for us,” Faria said. “And an issue with the yellow card to Paul is he is off the next match, so there is maybe reasons to express some frustration.

“After that of course there are also things that are part of the game and the referee took the decision on the sending off but, from our perspective, it was a decision that should be given to the opposite side.”

Mourinho was given a one-match touchline ban against Swansea City and an £8,000 fine after being sent to the stands during United’s goalless draw against Burnley last month for verbally abusing referee Mark Clattenburg in the tunnel at half-time. The Portuguese was warned on that occasion about his future conduct by the Football Association, who may now take a dim view of another unsavoury incident so soon after the Burnley offence.

Any charge would be the third Mourinho has faced this season after also being fined £50,000 for an outburst about referee Anthony Taylor in the build-up to United’s game against Liverpool at Anfield last month.