Breakaway European Super League founder and Juventus chairman Andrea Agnelli says the league can no longer go ahead after the six Premier League clubs withdrew.
Asked whether the project could still happen after the exits, Agnelli said: "To be frank and honest no, evidently that is not the case."
Soon after he spoke, La Liga side Atletico Madrid and the Serie A duo Inter Milan and AC Milan announced they were all also withdrawing from the Super League.
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Plans had been announced on Sunday for a midweek European Super League featuring 20 teams, which would include 15 founder members who would not be subject to possible relegation.
The 12 teams who had signed up included Arsenal, Chelsea, Liverpool, Manchester City, Manchester United and Tottenham from the Premier League, three clubs from La Liga, and three from Serie A, including Agnelli's Juventus.
However, following condemnation of the plans from figures throughout the sport and a wave of fan protests, the six Premier League clubs announced on Tuesday that they were withdrawing from the plans.
Agnelli has now admitted defeat with regard to the Super League, although he maintains the proposals represented the change he thinks is needed in European football.
"I remain convinced of the beauty of that project," said Agnelli.
"But admittedly, I don't think that the project is now still up and running."
In a statement, Juventus then said: "With reference to the press release issued by Juventus Football Club S.p.A. on April 19, 2021, relating to the project to create the Super League, and the subsequent public debate, the Club states that it is aware of the request and otherwise expressed intentions of some clubs to withdraw from said project, although the necessary procedures set out in the agreement between the clubs have not been completed.
"In this context, Juventus, while remaining convinced of the validity of the sporting, commercial and legal assumptions of the project, believes that it currently presents limited possibilities of being completed in the form in which it was originally conceived.
"Juventus remains committed to building long-term value for the Company and for the whole football movement."
Meanwhile, Rome street artist Laika MCMLIV created a mural overnight depicting Juventus president Agnelli stabbing a football and causing it to deflate.
The artwork is called "The Failed Coup" and refers to the failed Super League plans. It appeared close to the Italian FA (FIGC) headquarters in Via Giulio Caccini, right in the centre of the Italian capital.
The caption says: "They tried to give the final blow to the most beautiful game in the world, they tried to destroy the founding principle of the sport where everybody can compete and win.
"But instead, this time the "faithful to the tribe" prevailed over the shady business of those who wanted to pierce our dreams."
After Juventus' statement and Agnelli's comments emerged, Atletico Madrid subsequently announced: "The Atletico de Madrid Board of Directors, meeting this Wednesday morning, has decided to formally communicate to the Superliga and the rest of the founding clubs its decision not to finally formalize its adherence to the project.
"Atletico de Madrid made the decision last Monday to join this project in response to circumstances that no longer exist today.
"For the club, harmony is essential between all the groups that make up the rojiblanca family, especially our fans.
"The first team squad and their coach have shown their satisfaction with the club's decision, understanding that sporting merits must prevail over any other criteria."
The club's captain Koke posted on Twitter: "We want to express our satisfaction at the final decision taken by our club to withdraw from the Super project.
"We will continue fighting to help Atleti grow through the values of effort and sporting merit that have always characterised us, so that all of you continue to see yourself reflected in those signs of identity."
Inter Milan said in a statement: "FC Internazionale Milano confirms that the club is no longer part of the Super League project.
"We are always committed to giving the fans the best football experience; innovation and inclusion have been part of our DNA since our foundation. Our commitment with all stakeholders to improve the football industry will never change.
"Inter believe that football, like any sector of activity, should have an interest in constantly improving its competitions, in order to continue to excite fans of all ages all over the world, within a framework of financial sustainability.
"With this vision we will continue to work together with institutions and all stakeholders for the future of the sport we all love."
And AC Milan said: "We accepted the invitation to participate in the Super League project with the genuine intention to deliver the best possible European competition for football fans around the world and in the best interest of the club and our own fans.
"Change is not always easy, but evolution is necessary for progress, and the structures of European football have evolved and changed over the decades.
"However, the voices and the concerns of fans around the world have clearly been expressed about the Super League, and AC Milan must be sensitive to the voice of those who love this wonderful sport.
"We will continue to work hard to deliver a sustainable model for football."
AC Milan technical director Paolo Maldini has told Sky in Italy he was kept in the dark over plans for a proposed European Super League.
"I want to specify that I was not involved in discussions regarding the Super League," he said before his side's Serie A game against Sassuolo on Wednesday evening.
"I found out about it on Sunday night, after the joint statement from the other clubs. This was obviously decided at a higher level in the club than my own position. I felt a bit confused.
"That doesn't rule me out of taking responsibility for apologising to the fans, not just the Milan fans, but in general football fans, who felt betrayed by the principles of sport that we as Milan have always respected.
"It's something I feel the need to say. Naturally, the director of a big club in 2021 knows that revenue is important, that sustainability is important. So we need to ask ourselves if we can learn from this situation, can we learn where we can push ourselves to?
"We certainly cannot push past the values of sport and of meritocracy, which are made of dreams."
Italian FA: Juventus, Inter, and AC Milan will face no punishment for failed breakaway
Italian FA president Gabriele Gravina has ruled out Inter, Juventus and AC Milan being punished over their involvement in the failed Super League plans.
The 67-year-old, who was elected as a member of the UEFA Executive Committee at the UEFA Congress, said the debacle needs to act as a warning for the footballing world.
When asked whether the three Serie A clubs would be punished, Gravina said: "Absolutely not, we cannot sanction an idea which did not materialise.
"I'm not planning to meet with executives from the three clubs. We have a federal meeting on Monday, there won't be any form of indirect trial, sentencing or revenge.
"We strenuously defended the boundaries of the values and rules in the world of football and it seems like everything has returned to normality, but it's a warning which needs to make us think about the fact that something is not working, and I will do it as an executive taking all my responsibilities."
Premier League clubs withdraw from Super League
Manchester City became the first Premier League side to publicly confirm they were pulling out of the breakaway competition, with a statement reading: "Manchester City Football Club can confirm that it has formally enacted the procedures to withdraw from the group developing plans for a European Super League."
In a statement to their supporters confirming their withdrawal, Arsenal said: "We made a mistake, and we apologise for it.
"We know it will take time to restore your faith in what we are trying to achieve here at Arsenal but let us be clear that the decision to be part of the Super League was driven by our desire to protect Arsenal, the club you love, and to support the game you love through greater solidarity and financial stability."
In their statement, Manchester United said: "We have listened carefully to the reaction from our fans, the UK government and other key stakeholders. We remain committed to working with others across the football community to come up with sustainable solutions to the long-term challenges facing the game."
In confirming their withdrawal from the plans, Liverpool stated: "In recent days, the club has received representations from various key stakeholders, both internally and externally, and we would like to thank them for their valuable contributions."
Tottenham chairman Daniel Levy told his club's website: "We regret the anxiety and upset caused by the ESL proposal. We felt it was important that our club participated in the development of a possible new structure that sought to better ensure financial fair play and financial sustainability whilst delivering significantly increased support for the wider football pyramid."
A Chelsea statement in the early hours of Wednesday morning said: "We have now had time to consider the matter fully and have decided that our continued participation in these plans would not be in the best interests of the club, our supporters or the wider football community."