Students face frequent formal and informal tests, both in the academic context and social life. On each of these occasions, they risk falling short of their own or others' expectations. Facing failure is a psychological challenge, and people can react with defensive strategies, which may have negative consequences. Here we investigated the role of self-esteem as a possible buffer against these defensive strategies. Previous research has demonstrated that, in the face of failure, individuals with discrepant (fragile: high explicit and low implicit, or damaged: high implicit and low explicit) self-esteem are more likely to engage in defensive mechanisms than individuals with consistent implicit and explicit self-esteem. Two studies investigate the relationship between implicit and explicit self-esteem and two defensive strategies against the threat of failure: subjective overachievement and retroactive excuses. In Study 1 (N = 176 high school students), we find an association between fragile self-esteem and subjective overachievement. In Study 2 (N = 101 university students), damaged self-esteem is related to the increased use of retroactive excuses as a form of self-serving bias. These results add to the growing body of evidence documenting the maladaptive nature of fragile and damaged self-esteem.