Marca published an extract Thursday from a letter it received from Mourinho's law firm stating that journalist Roberto Palomar "referred to our client as 'the type of person who would flee after knocking someone down.'"
The letter adds that "this is degrading and was used in a manner which was completely unnecessary in the critique."
Mourinho's relationship with the Spanish media has always been tetchy since his arrival in 2010, but has heightened during a current run of poor results.
Mourinho is demanding €15,000 ($19,600) in damages, which his firm says the coach would donate to his son's local football team.
