Manager Marco Silva will also serve a two-game touchline ban and has been fined £40,000 after being sent off in the same game following Mitrovic’s dismissal in the 72nd minute.
Mitrovic was given an automatic three-match suspension after receiving a straight red card for pushing Kavanagh as he protested against Willian’s red card for blocking a shot on the goal line with his hand.
A further three matches were added to the Serbian’s punishment as a regulatory commission deemed him to have committed violent conduct towards the official. The commission increased the ban further after the striker admitted to making “improper, abusive, insulting and threatening” language and behaviour towards an official.
The Football Association could push for an even longer suspension for both Mitrovic and Silva after confirming that it plans to appeal the regulatory commission’s decision.
An FA spokesperson said: “We note the decision of the independent regulatory commission to sanction Aleksandar Mitrovic and Marco Silva.
“Our current intention is to appeal both sanctions, however we will await the written reasons before confirming our final position.”
Mitrovic was always likely to face a longer suspension than the regular three-match minimum for a straight red card after the FA made clear that retrospective action would be taken.
“The FA has claimed that the standard punishment which would otherwise apply to Aleksandar Mitrovic for the sending off offence of violent conduct that he committed towards the match referee is clearly insufficient,” the organisation said after the game.
“In addition, Aleksandar Mitrovic’s behaviour and/or language was allegedly improper and/or abusive and/or insulting and/or threatening following his dismissal.”
Mitrovic has already served one game of his suspension after missing the 2-1 defeat against Bournemouth and will not be available for selection again until Fulham’s game against Southampton on 13 May.
Fulham were also fined £40,000 for failing to “ensure its players conducted themselves in an orderly fashion”.
The incident also brought the treatment of referees from the elite level of the sport down to grassroots under the microscope, with officials calling for Mitrovic to be handed a lengthy ban to set a precedent.
“The Mitrovic incident in the Manchester United vs Fulham FA Cup quarter final is a chance for the FA to become a true game-changer and send out a strong message that this is unacceptable behaviour and that we must protect referees at all levels,” Martin Cassidy, chief executive of charity Ref Support UK, told i.
Last week, an i investigation into the refereeing crisis found that assaults, threatening behaviour, intimidation and racism are occurring in grass-roots football “every weekend”, which is leading to a chronic shortage of officials.