UEFA president Aleksander Ceferin says the remaining Super League clubs Barcelona, Real Madrid and Juventus could yet face sanctions, also insisting they are free to form their own competition if they give up their places in the Champions League.
Madrid, Barcelona, and Juventus were the only three founding clubs not to renounce their backing for the widely derided Super League after the breakaway project's collapse in April 2021.
Last month, a Madrid court lifted precautionary measures preventing UEFA from punishing the trio, who have continued to voice their backing for a new competition – to be governed by its founding clubs – despite the withdrawals of the other nine founding members.
Speaking to AS, Ceferin hinted sanctions against the trio could be on the horizon and hit out at the "incredible arrogance" of the clubs.
Ceferin, who assumed his post in 2016 after succeeding Michel Platini, also said the clubs were free to do whatever they liked, but would not be allowed to participate in UEFA competitions if the venture was revived.
"Of course it's possible [to sanction the clubs] but let's see what happens," he said. "The only 'hello' UEFA got from them came from the courts, as they tried to challenge us everywhere.
"We never said that they couldn't play their own competition, because they can if they want. But it's funny that these were the clubs that first registered in the Champions League.
"If they play other tournaments, they cannot play in our competitions. That is not a monopoly. They can create their own UEFA and do what they think is right.
"I showed them a lot of respect in the past. I don't want to talk about the president of Juventus [Andrea Agnelli], but my relationship with him was very open and honest.
"I never said this before, but I invited the president of Madrid, Florentino Perez, to Nyon before it all happened to talk about future competitions. He called off the meeting with a text message just 24 hours earlier because of 'a basketball-related event'. With [former Barca president Josep Maria] Bartomeu I never spoke.
"Everyone had a chance to speak, and we've never been pushy or arrogant. The announcement of that project was an act of incredible arrogance on their part, and that's probably why they don't want to communicate with UEFA.
"But that has never influenced how we treat them in our tournaments. You can see it in their successes: Real Madrid will play in the Champions League final and Barca will play in the Women's Champions League. That is a clear sign that our competitions are healthy, fair and correct.
"Football must remain open to all, and we will not back down one millimetre to defend the European sporting model. What they want is theirs, and they are free to get together and do what they want."
Amid their refusal to back down on their support for the Super League, Real Madrid will appear in their 17th European Cup/Champions League final later this month after a remarkable 6-5 aggregate triumph over Manchester City in the semi-finals.
Meanwhile, although UEFA has faced criticism for proposed Champions League reforms which could allow two qualification places to be awarded based on historical performances, Ceferin said the demise of the Super League made clear that continental football must remain open to all.
"I was glad it happened because it was always up in the air," he added. "When it finally came out, we ended once and for all with this nonsense that football can be bought, that football is only for the elite, only for the rich.
"That will never happen. People warned me that the same people killed basketball, but I told them, 'Basketball is not football. It will never be football.' Football is part of our history. It is part of our traditions."