Referee Miguel Ayza Gamez claims Real Madrid defender Sergio Ramos insulted him during a Copa del Rey match at the Santiago Bernabeu.
The Spain international was handed a second yellow card for kicking out at Augusto Fernandez in the 73rd minute of Madrid's 4-0 win over Celta Vigo on Wednesday.
The 26-year-old verbally attacked the referee before walking off as he felt he was being treated unfairly.
Ramos now faces an extended stint on the sidelines after the incident, with 'insulting, offending or showing an offensive attitude towards the referee' punishable by between four and 12 games.
"You're a scoundrel. You have been trying to screw us all game long," the defender repeatedly said to the referee, according to his post-match report.
The centre-back then went on to insult the fourth official, too, before making way to the dressing room.
"On his way out, he approached the fourth official, saying: 'It's the same as always you scoundrels'," the report read.
Meanwhile, Ramos later acknowledged that he verbally attacked the referee after his dismissal.
"I am disappointed with the red card. I know this referee for quite some time now and I have never had a good feeling about him," he said.
"Sometimes you say things in the heat of the moment that you shouldn't say. I apologise for that."
Madrid qualified for the quarter-final of the competition following Wednesday's victory, after losing the first leg 2-1.