The Russian-Ukraine gas supply crisis in January 2009 brought an unprecedented disruption for the gas supply in Europe. As a response, the SoS Regulation put in place an ambitious plan to mitigate not only the risks of another gas supply crisis, but also to protect a defined group of customers in case of unavoidable gas shortage - households, small and medium enterprises, institutions providing essential social services among others. While it was thought the SoS Regulation had pursued exhaustive harmonization standards in the definition of protected costumers, the ECJ's judgment in Eni and Others reopened the question. This article, instead, argues that the Court got it wrong. Neither the judgment nor the opinion of the Advocate General took into sufficient account the legal content Fof the provision that defined protected customers. If the Court had done so, the judgment would have likely taken additional linguistic, systemic, and teleological arguments into account. The analyses and comments on Eni and Others here offered focus on the first referred question about whether Member States could impose additional obligation on gas undertakings by reviewing the definition of protected customer.