Introduction: Countermovement jump (CMJ) and perceived wellness measures are useful for monitoring fatigue. Fatigue indicators should simultaneously show sensitivity to previous load and demonstrate influence on subsequent physical output; however, this has not been examined. This study examined the efficacy of CMJ and wellness measures to both detect post-match fatigue and predict subsequent physical match output in elite youth soccer. Methods: Sixteen soccer players (18 ± 1 years) participated in 36 English Football League Youth Alliance League fixtures. Physical match outputs (total distance, high-speed running, very high-speed running, and accelerations and decelerations) were recorded using a 10 Hz global positioning system and 200 Hz accelerometer device during competitive match play. CMJ height and perceived wellness were assessed weekly and daily, respectively, as indirect indicators of fatigue. Four sub-units of wellness (perceived soreness, energy, general stress, and sleep) were measured using customised psychometric questionnaires. Results: Simple linear regression showed that match accelerations and decelerations (AD) were predictive of energy (R2 = 0.08, P = 0.001), stress (R2 = 0.09, P < 0.001), and total wellness (R2 = 0.06, P = 0.002) 2 days post-match. CMJ (R2 = 0.05, P = 0.002), stress (R2 = 0.08, P < 0.001), sleep (R2 = 0.03, P = 0.034), and total wellness (R2 = 0.05, P = 0.006) 5 days pre-match (MD-5) were predictive of AD during the subsequent match. Conclusion: CMJ and wellness may be useful in detecting post-match fatigue. Wellness scores, but not CMJ, on MD-5 influence subsequent match output and therefore may be used to plan and periodise training for the upcoming microcycle.