Real Madrid, Barcelona and Juventus on Saturday defended the aborted Super League project after European football governing body UEFA threatened them with sanctions.
In a joint statement, the three clubs said the Super League had been launched "with the aim of providing solutions to the current unsustainable situation in the football industry."
They argued that they and the nine clubs who withdrew under pressure from supporters' protests, including Manchester United, Chelsea and Liverpool among others, "shared the same concerns ... that structural reforms are indispensable to ensure our sport stays appealing and survives in the long term."
They reiterated that the issues that led to the creation of the Super League have not gone away, and therefore they still have "the duty to act in a responsible manner and persevere in the pursuit of adequate solutions, despite the unacceptable and ongoing pressures and threats received from UEFA."
UEFA to 'take whatever action it deems appropriate'
On Friday, UEFA said it reserved all rights to "take whatever action it deems appropriate" against the clubs who haven't abandoned their Super League ambitions.
The other nine clubs involved have acknowledged and accepted "that the Super League project was a mistake," UEFA said.
Those nine clubs agreed to forego 5% of their revenue from UEFA competitions for one season and between them make a €15 million ($18.25 million) donation to support grassroots and youth football in Europe.
They also committed to participating in UEFA competitions for which they qualify and agreed to pay fines of 100 million euros if they ever seek to play in an "unauthorized" competition.
"The founding clubs have suffered, and continue to suffer, unacceptable third-party pressures, threats, and offenses to abandon the project," Real Madrid, Barcelona and Juventus said in their statement.
"This is intolerable under the rule of law and tribunals have already ruled in favor of the Super League proposal, ordering FIFA and UEFA to, either directly or through their affiliated bodies, refrain from taking any action which may hinder this initiative in any way while court proceedings are pending," the clubs said.
'Highly irresponsible' to abandon Super League
A breakaway Super League set up by 12 clubs was announced last month but fell apart after 48 hours.
The Super League argued it would increase revenue for the top clubs in Europe and allow them to distribute more money to the rest of the game.
UEFA, other teams and fan organizations, however, said the league would only boost the power and wealth of elite clubs.
Juventus, Real Madrid and Barcelona said they were ready to reconsider the proposed approach of the breakaway project following the backlash but said it would be "highly irresponsible" for them to abandon the project.
"We are fully aware of the diversity of reactions to the Super League initiative and, consequently, of the need to reflect on the reasons for some of them," their statement added.
"We are ready to reconsider the proposed approach, as necessary.
"However, we would be highly irresponsible if, being aware of the needs and systemic crisis in the football sector... we abandoned such mission to provide effective and sustainable answers to the existential questions that threaten the football industry."
sri/nm (dpa, AFP, Reuters)