The decision delivered by the European Court of Justice in “Android Auto” may represent a watershed moment in competition policy for digital markets. By requiring dominant platforms to accommodate third-party requests to enable interoperability, the judgment could significantly affect their design and business models, with effects extending well beyond the geographical boundaries of the EU. In this regard, from a transatlantic perspective, the judgment deepens the traditional divide with the U.S. approach to refusal to deal and may prove more disruptive than the European Digital Markets Act (DMA). To this end, and in contrast with the much-celebrated Brussels effect, the paper investigates whether the principle affirmed by the Luxembourg judges may prove more effective in advancing the DMA’s objective of achieving interoperability by design.