The recent years have witnessed a significant change in China-EUrope relations, with the EU's strategic positioning of China undergoing a fundamental shift from a "partner" to a "systemic rival." By applying a theoretical framework based on neoclassical realism, the present paper examines the determinant factors leading to such a shift. This study highlights three factors: first, a change in the US's strategy and governance capability; second, the power symmetries between China and EUrope, including salient changes in material strength and marked differences in norms; third, an emergent change in strategic culture, encompassing a striving China visà-vis a strategically autonomous EUrope. By following Götz's (2021) insights on neoclassical realist approaches that employ intervening variables as complementary factors, we identify the US factor as the most important international factor in structural terms, while the power symmetries and strategic culture act as complementary factors. The paper concludes that while maintaining engagement, China-EUrope relations will only see further intensified rivalry and contradictions in the future.