UEFA and FIFA's right to block new competitions like the European Super League is compatible with EU law, according to a key legal opinion published on Thursday.The opinion of the Advocate General in the case, Athanasios Rantos, was read out on Thursday morning at the European Court of Justice in Luxembourg.Those behind the Super League felt UEFA and FIFA were abusing a dominant position under EU competition law by first blocking the league in April 2021 and then seeking to sanction the clubs involved.Although this opinion is non-binding ahead of the final ruling next year, it appears to sink any hopes of a Super League operating within European football's mainstream if it does not have UEFA and FIFA approval.A release from the court stated: "While ESLC (European Super League Company) is free to set up its own independent football competition outside the UEFA and FIFA ecosystem, it cannot however, in parallel with the creation of such a competition, continue to participate in the football competitions organised by FIFA and UEFA without the prior authorisation of those federations."That would effectively mean clubs would be free to break away and join an unapproved Super League, but would not also be able to compete in domestic leagues.UEFA said it "warmly welcomed" the AG opinion which it described as "unequivocal".Listen to the RTÉ Soccer podcast on Apple Podcasts, Spotify or wherever you get your podcasts.We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity.