Bayern Munich CEO Jan-Christian Dreesen said Thursday a European Super League would be "an attack on the importance of national leagues", while reaffirming "the door to the Super League remains closed at Bayern".
Dreesen was responding to Thursday's European Court of Justice ruling that UEFA broke EU law in blocking the rival competition.
Bayern were not one of the 12 clubs to initially sign up to the Super League in 2021, saying they rejected the idea.
"We have taken note of the judgment of the European Court of Justice," said Dreesen.
"However, this does not change the attitude of FC Bayern and the attitude of the European Clubs Association that such a competition would represent an attack on the importance of the national leagues and the equilibrium of European football."
Six-time European champions Bayern have consistently expressed their opposition to any breakaway plans.
"The Bundesliga forms the foundation of FC Bayern, just as all national leagues form the foundation of European football clubs," Dreesen's statement continued.
"Therefore, it is our duty and our deep conviction to strengthen them, not weaken them.
"We also support the European club competitions under the umbrella of UEFA. So once again it's very clear: the door for the Super League at FC Bayern remains closed."
German clubs, unlike those in other major European leagues, must comply with the so-called 50+1 rule, which mandates member control of operations.
