This study empirically investigates the influence of competitive anxiety and sport motivation on the performance outcomes of student-athletes. Grounded in Self-Determination Theory (SDT) and cognitive-motivational models of anxiety, the research analyzes the interaction mechanisms between anxiety and various forms of motivational regulation. A cross-sectional survey was conducted with $N=200$ university student-athletes in Tashkent. Data were collected using validated psychometric instruments: the Sport Anxiety Scale–2 (SAS-2) and an adapted version of the Sport Motivation Scale (AMS-Sport). Hierarchical regression analyses revealed that competitive anxiety serves as a significant negative predictor of sport performance ($\beta = -0.25, p < 0.01$), whereas motivation exerts a robust positive effect ($\beta = 0.58, p < 0.001$). The interaction term was statistically significant ($\beta = 0.12, p < 0.01$), confirming the hypothesis of a buffering role of motivation: high levels of autonomous motivation effectively attenuate the deleterious impact of anxiety on performance. These findings emphasize the necessity of implementing psychological training programs focused on developing intrinsic motivation and stress-management skills within university sport systems.