Sion's hopes of regaining their place in the Europa League group phase have been dealt a blow after UEFA's member associations emphatically threw their support behind the governing body's decision to expel the Swiss club.
In a statement entitled 'Declaration of the 53 UEFA member associations regarding the FC Sion case', the member nations warned that any club that refused to accept the rules of the football family "should not participate in it".
"The 53 national associations of UEFA have today unanimously declared their support for UEFA President Michel Platini, the UEFA Executive Committee, the UEFA General Secretary, the UEFA disciplinary bodies and the UEFA administration for their determination to uphold the statutes and regulations of football," the statement read.
"The European national associations call upon both FIFA and the Swiss FA to urgently take concrete steps to uphold the statutes and regulations of FIFA, as UEFA has done.
"The independent sports justice system is the best guarantor of equality and fairness for all participants in sports.
"The European National Associations declare that any member of the football family which refuses to accept the rules of the competition should not participate in it."
Sion were thrown out of the Europa League on September 2 after being found guilty of naming five ineligible players, with Celtic handed their place in the group stages despite losing their play-off tie 3-1 on aggregate. The club have been waging a battle in the Swiss courts in an effort to be reinstated
UEFA's emergency panel last Tuesday dismissed a ruling from the district court in Vaud that Sion should be allowed back in the competition, while on Thursday the same court ruled that the opening round of Europa League Group I fixtures, including a 2-0 defeat for Celtic at Atletico Madrid, were invalid.
After UEFA's disciplinary body threw out Sion's initial appeal last week, the club responded by announcing they would take action against UEFA, looking for initial compensation of over four million euros (Â£3.47million), and potentially tens of millions in the long term.
"UEFA believes that it rules the world," a Sion spokesman said at the time.