LaLiga president Javier Tebas believes the proposals to radically reform European club football from 2024 onward are "a disaster" and there is no need to change the current format at all.
European football's governing body UEFA is currently leading what it describes as an unprecedented consultation exercise on the future of the Champions League, Europa League and Europa League 2, which is scheduled to start in 2021.
But the debate has already splintered into two opposing camps, with the elite clubs, represented by the European Club Association, on one side, and domestic leagues, represented by European Leagues, on the other, with UEFA trying to keep the peace in the middle.
The cause of the increasingly bitter row is the perception that the process is being driven by Europe's richest clubs.
The ECA and UEFA deny this but their claims are slightly undermined by the fact that the consultation has started with a proposal on the table to increase the number of European games and introduce a promotion/relegation system which would reduce the number of Champions League slots available to qualifiers from domestic competitions.
Last week, league meetings in Germany and France rejected this plan, which has been championed by ECA and Juventus president Andrea Agnelli, while the Premier League has also made its opposition clear. But few have been as vocal in their criticism of the proposed changes as Tebas.
Speaking at the Financial Times' Business of Football Summit in London today, the Spaniard said: "The proposals from the ECA and UEFA are a disaster for European football. They would destroy domestic leagues by relegating them to the fourth tier of European competition.
"They would concentrate even more wealth at the top and essentially close the top tier - we can't allow that to happen."
Asked what he would do instead, Tebas said: "I would propose not to change it at all.
"These proposals are not to reform the Champions League, they are to create an entirely new competition. We don't need that. What we have is working."
While Tebas was speaking, the ECA issued a statement following a meeting of its executive board in St Petersburg.
It said that it was still approaching this consultation on the future with "the aim of evolving a vision for a fair, balanced and representative model which will be of more benefit to the club game across all of Europe, from the smallest to the biggest clubs".
It added that it believes in a "football ecosystem where more games of quality can take place on the European stage at all levels", "greater diversity and financial stability across the competitions" and a "broader and deeper base of clubs competing and developing over time".
The organisation, which says it represents more than 230 clubs, will next discuss the issue with its members at its general assembly in Malta on June 6-7.
Whether it heeds European Leagues' call last week to restart the reform consultation "from scratch" is unclear but Agnelli's original plan would appear to have little chance of success without significant compromises.