Ukrainian President Zelensky’s visit to Belgrade and discussions of potential arms cooperation with Serbia are exposing limitations in Russia’s Balkan policy. Despite Serbian President Vucic’s prior close ties to Moscow, Russia has shown surprising tolerance for this developing relationship with Ukraine. This apparent inaction suggests a stalling of Russian efforts to maintain influence in the region, mirroring challenges faced in the ongoing conflict in Ukraine. Experts suggest Moscow's policies are showing inertia, failing to effectively counter shifting dynamics. The situation raises questions about Russia’s ability to project power and pursue its strategic objectives in the Balkans. This passivity could create opportunities for other actors, including the West, to increase their engagement. Ultimately, Zelensky’s visit underscores a significant shift in the geopolitical landscape of the Western Balkans.