<p>Mental fatigue is a well-documented performance inhibitor in team sports, Therefore, identifying strategies to attenuate mental fatigue seems necessary. This study aimed to evaluate and compare four distinct training models—Modified Stroop, SAFT⁹⁰, T-SAFT⁹⁰, and a combined T-SAFT⁹⁰ + Stroop protocol—to identify the most effective method for inducing mental fatigue under controlled laboratory conditions, as a potential model for brain endurance training (BET) research in young soccer players. Fifteen male players (aged 16–18) participated in a randomized cross-over study. Mental fatigue was assessed via a Visual Analogue Scale (VAS; primary outcome), cognitive performance (secondary outcomes) was evaluated through response time, response accuracy, working memory capacity, visual Scanning Identification, and auditory pattern recognition. Technical performance was measured using penalty time, movement time and passing accuracy in the Loughborough Soccer Passing Test (LSPT; primary outcomes). All protocols significantly increased mental fatigue, with the largest effect observed in the combined T-SAFT⁹⁰ + Stroop model. Response accuracy declined across all models, while response time worsened in the Stroop and T-SAFT⁹⁰ conditions. Penalty time increased in the Stroop and T-SAFT⁹⁰ protocols, whereas passing accuracy decreased most significantly in the combined model. In summary, under standardized, controlled conditions, the combined cognitive-physical training model induced the highest mental fatigue and most consistently altered cognitive and technical performance. These findings provide preliminary evidence supporting its potential as a BET model for research and structured training environments, though ecological validation in real soccer contexts remains necessary.</p>