This study aimed to compare the effects of coach encouragement during the on-court tennis training drills (OTDs) on the psychophysiological and performance responses of young tennis players. Twenty-five young male tennis players (14.0 ± 0.3 years of age) performed six bouts of each of the four common OTDs; Star, Suicide, Box and Big X (30:60 s; 1:2 work to rest ratio). The heart rate (HR) and total distance covered were monitored using two portable multivariable integrated 10 Hz GPS monitoring devices during all OTDs, and the rating of perceived exertion (RPE-10) and short form Physical Activity Enjoyment Scale (PACES) values were determined after each OTDs bout. The results demonstrated that OTDs with coach encouragement induced significantly higher psychophysiological and performance responses compared to OTDs without coach encouragement (p < 0.05). The results of this study confirm that coach encouragement improves the intensity, performance and physical enjoyment level during OTDs. These findings might inform training practices in youth tennis players in order to improve tennis performance.