Individuals tend to compare themselves with others, and the results of these self-evaluations influence subsequent performance. When individuals perceive an advantage over their rivals (challenge-type response), they achieve higher levels of performance. According to the biopsychosocial model of challenge and threat, benefits of favourable appraisals are partly mediated by cardiovascular efficiency, which is increased by challenge and decreased by threat evaluations. In this study, we tested whether the biopsychosocial model can be extended to predict behavioural outcomes in esports. We expected that challenge-type evaluations would increase performance compared to threat-type evaluations. Eighty-two men were assigned to a challenge or threat group and completed three rounds of Counter-Strike: Global Offensive – a video game popular in esports. Individuals with the highest scores were awarded cash prizes. Cardiovascular markers of challenge and threat, cognitive appraisals, and game scores were recorded. We manipulated the social challenge and social threat evaluation by informing participants that their performance in the initial round was superior (challenge) or inferior (threat) compared with other gamers. We found that individuals with more gaming experience, believed they were better than other gamers, had higher heart rate and, in turn, achieved higher scores. These effects were related to initial situational appraisal at the baseline and were not boosted by feedback provided during the actual performance. These results are the first to document that social comparisons among gamers are accurate in the prediction of future physiological and behavioural outcomes. Furthermore, these findings emphasize that physiological responses mediate relationships between action-related cognitions and performance.