Rangers may have to play Swiss side Young Boys in an empty stadium if UEFA announce charges for alleged racist and sectarian behaviour by fans in Rotterdam.
Record Sport reporter Gary Ralston and other journalists present reported hearing such chants in the stadium, an infraction that has the potential for very severe consequences.
UEFA’s Control, Ethics and Disciplinary Body have already closed off sections of Ibrox as a result of previous illicit singing, against St Josephs and Legia Warsaw, and a third charge would likely see a full stadium closure.
The Article 14 rules on racism and other discriminatory conduct state: "If one or more of a member association or club’s supporters engage in the behaviour described in paragraph 1, the member association or club responsible is punished with a minimum of a partial stadium closure.
"The following disciplinary measures apply in the event of recidivism: a. a second offence is punished with one match played behind closed doors and a fine of € 50,000; b. any subsequent offence is punished with more than one match behind closed doors, a stadium closure, the forfeiting of a match, the deduction of points and/or disqualification from the competition.
"If the circumstances of the case require it, the competent disciplinary body may impose additional disciplinary measures on the member association or club responsible, such as the playing of one or more matches behind closed doors, a stadium closure, the forfeiting of a match, the deduction of points and/or disqualification from the competition."
Record Sport understands club are likely to find out early next week if they face sanction.
Rangers avoided playing their first match of Group G against Feyenoord behind closed doors after they refused to take tickets to the second fixture of the group against Young Boys.
They also released a strongly worded statement stating: "Those fans responsible for this partial closure of Ibrox Stadium need to understand that they are damaging our club. If there is a further incidence at tomorrow night’s match this could lead to a ground closure.
"The same applies to those who indulged in sectarian singing in Warsaw last week and that is why we have taken the decision to make UEFA aware that we will decline tickets for our next away match even though this means that, once again, the many must suffer because of the few.
"This kind of behaviour has no place at Ibrox, or anywhere else where our many teams appear. Offenders must please stop. You are endangering your club which has recently launched its Everyone Anyone project aimed at welcoming all to Ibrox.
"Those who wish to sing offensive songs must realise by now that they are insulting Rangers players, staff, and fellow fans.
"There is nothing clever, bold or even defiant in what this small number of supporters are doing.
"By supporting Rangers in the correct way the rest of us must strive to protect our great club. One way or another this offensive behaviour must end and it would be much more preferable if we stopped it ourselves, simply by behaving like true Rangers fans."
