The European Court of Justice declared that Uefa and Fifa were "abusing a dominant position" by forbidding clubs from entering a European Super League, which was illegal.
It follows a lawsuit filed by the ESL and its supporters, who claimed that by threatening to impose sanctions on those who joined the breakaway league, Uefa and Fifa were violating competition laws, reported BBC.
The European Union's top court found against the governing bodies.
It further stated that this did not imply that a breakaway league would "necessarily be approved".
On a day that is extremely important to European football:
1 Uefa stated that it was "confident in the robustness" of the regulations behind ESL supporters A22's updated proposals.
2 Clubs are "masters of their own destiny," according to Real Madrid.
3 La Liga referred to the ESL as a "selfish and elitist model"
An earlier report released in December by the ECJ said the regulations of football's European and world governing bodies were "compatible with EU competition law".
The ruling will be perceived as a blow to the authority of Uefa and Fifa and how they administer the game.
Uefa said it was "confident in the robustness" of rules it has brought in since the ESL was first proposed, and that it would "comply with all relevant European laws and regulations".
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