Louis van Gaal has been charged by the Football Association for comments "alleging or implying bias" by referee Chris Foy following Man-chester United's FA Cup fourth-round draw at Cambridge United.
Van Gaal, whose United team progressed to the fifth round with a 3-0 replay victory against the League Two club at Old Trafford on Tuesday, was angered by Foy's performance during the first game at the Abbey Stadium.
"We know in advance everything is against us," Van Gaal said after the 0-0 draw. "We have to come here, the pitch is not so good but that can influence also that you play in another style and the opponents are always giving a lot more than normally and defending is always easier than attacking.
"And then you have seen the referee, it's always the same. Every-where I have coached these games, and I have coached them with other clubs, it's always the same."
Van Gaal's comments about Foy have triggered action by the FA, however, with a statement released last night confirming a charge against the Dutchman. He has until 6pm on Monday to respond.
Should Van Gaal accept the charge, or be found guilty, he is likely to be fined or warned by the FA, rather than receive a touchline ban, because off-field punishments are generally issued for off-field offences.
Meanwhile, United have been given encouragement in their efforts to extend the contract of David de Gea following claims by the goalkeeper's agent, Jorge Mendes, that the player was happy at Old Trafford.
De Gea, an ever-present for United this season, has yet to commit to a new long-term deal, despite having less than 18 months to run on his deal, which expires in June 2016.
Having emerged as the likely successor to Iker Casillas as Spain's No?1, De Gea has become a target for Real Madrid, who are prepared to wait until next year to sign the former Atletico Madrid youngster on a free transfer. But while stopping short of insisting that De Gea would put pen to paper on a new contract at United, Mendes hinted that the 24-year-old would ultimately decide to extend his stay.
"De Gea has one year left on his contract and I think that he will stay in Manchester," Mendes told the BBC. "The player will decide, but he's happy there, at the moment."
United are understood to be ready to make De Gea one of the highest-paid players in the Premier League, but with the keeper's pop-star girlfriend still based in Madrid, his future remains in the balance and could yet rest on whether Van Gaal's team secure a return to the Champions League this season.
Mendes, who also acts for United's on-loan forward Radamel Falcao, reiterated his belief that the Colombian forward would earn a move to one of the "biggest teams in Europe'' if United turned down the option of signing him permanently from Monaco for a pre-agreed pounds 43.2?million this summer.
Having struck a close working relationship with former United manager Sir Alex Ferguson, Mendes has admitted that he has not been surprised by the club's struggles since the Scot retired in May 2013.
In a thinly-veiled swipe at Van Gaal, Mendes claimed that only Joes Mourinho possessed the personality and track record capable of matching that of Ferguson.
"Manchester United has just one problem," Mendes said. "It's completely impossible to find someone like Sir Alex Ferguson because he's a god, he's a genius and to find a genius is very difficult. You have one in England - Jose Mourinho. Having Sir Alex Ferguson ensures at this moment you [United] have 12 or 15 points more. He's finished his career, but he's someone that [makes] the difference."
With Mourinho 18 months into his second spell as Chelsea manager, Mendes claimed that he would spend more than a decade at Stamford Bridge this time around.
Meanwhile, United midfielder Ander Herrera is due to appear in court in Spain the day after the Premier League encounter with Newcastle United next month, with the player one of 41 people due to give evidence over alleged match-fixing during a fixture between Levante and Real Zaragoza in 2011.
Herrera, 25, denies any involvement in match-fixing.