Manchester United are set to make a formal complaint over the denial of a second penalty in Friday's Premier League draw with Bournemouth.
It is understood the Red Devils will contact refereeing body the PGMO on Saturday, with club officials furious about a second-half incident involving Amad Diallo.
Diallo appeared to be pulled to the ground in the penalty area moments before Ryan Christie equalised for Bournemouth.
Referee Stuart Attwell decided not to give the decision on the field and it was not overturned by VAR.
A James Hill own goal put United back ahead but, to rub salt into the wound, Bournemouth were then awarded a penalty for a push by Harry Maguire, who was sent off, with the game ending 2-2.
It is not the first time this season United have felt wronged by decision-making, including when Attwell disallowed a goal against Burnley, while they were also unhappy with nine minutes of added time.
United’s interim manager Michael Carrick branded Attwell’s decision making "baffling" and "astonishing" in his post-match press conference.
He said he had not spoken to Attwell after the final whistle and will take no comfort if the PGMO admits a mistake was made.
"It’s kind of, once it’s done, it’s done," said Carrick. "You can have all the conversations in the world about could it have been this, could it have been that?
"I just think that’s for VAR. If they’ve already given one and agreed that that was a penalty, then surely the next one should be a straightforward one? After it, there’s no point, whatever comes. Whether they apologise or not, it’s done now."
United remain in a strong position in terms of Champions League qualification but victory would have seen them close the gap to Manchester City to four points ahead of the international break.
