Jose Mourinho was fined for putting "an additional layer of pressure" on referee Anthony Taylor before Manchester United's Premier League game with Liverpool last month, the FA said.
The Portuguese coach, 53, was fined £50,000 by the Football Association for his comments prior to the 0-0 draw.
He said choosing Taylor put "pressure" on the Manchester-based official.
On Wednesday the FA said his remarks meant the referee "was damned if he did and damned if he didn't".
As well as a fine, Mourinho was also warned about his future conduct after an independent regulatory commission found he had brought the game into disrepute.
A document detailing the written reasons for Mourinho's punishment stated: "The referee's performance in the game appeared to have been unaffected by this additional pressure.
"Nonetheless, the regulatory commission judged Mr Mourinho's comments to have brought the game into disrepute."