The Portuguese criticised the official's performance following his team's 2-1 Premier League defeat at Burnley on Monday evening and the Press Association reports that he has now been asked to explain those remarks by the game's national governing body.

Nuno told Sky Sports after the match: "The referee does not have the quality to whistle a game in the Premier League.

"It is not about the crucial mistakes or decisions, it is about the way he handles the game. The players get nervous, too much voices, he whistles by the voices when some players are shouting.

"We are talking about the best competition and clearly he doesn't have the quality to whistle the game. I'm very disappointed to say this but I would not feel right if I didn't say it.

"I just don't want to see him more - that's what I told him. I hope he doesn't whistle a game of ours again because all the games we have with Lee Mason are always the same.

"He cannot control the players, the players are constantly arguing - both teams. With all the other referees the game flows, there's dialogue. He's just not ready to do it."

Nuno's side were arguably lucky to finish the match with 11 men after Joao Moutinho survived a VAR check on what looked like a stamp in stoppage time, while their goal came from the penalty spot after Fabio Silva was fouled by Josh Benson late on.

Post-match comments about a referee's performance are permitted under FA regulations provided they do not imply bias, attack an official's integrity, are not personally offensive, prolonged or particularly unreasonable.

Such incidents do not always lead to an FA charge, which would be based on a decision around the seriousness of the case and the track record of the individual who made the comments.

The FA may choose to issue a formal warning, remind the individual of their responsibilities or take no action.

Mason is the video assistant referee for Manchester City's home game against Newcastle on Boxing Day and will be the fourth official at the West Ham vs Brighton match the following day.