Martinez admitted a charge of misconduct from the Football Association for comments made to the press while feeling frustrated about Danny Welbeck being awarded a penalty.
A statement on the FA website read: "The charge was in relation to a breach of FA Rule E3 concerning media comments which implied that the match referee and/or match officials in general are motivated by bias and/or brought the game into disrepute.
Martinez, who had requested a personal hearing, was also warned as to his future conduct."
Source: FOOTYMAD
