Tennis matches are intense, of long induration, with brief recovery periods, played in hot environments. This subjects elite tennis athlete to heat stress. Whether high core temperature impacts performance, and whether performance decrements are attenuated with cooling, remains unknown. Three studies evaluated heat stress on rectal temperature (Tre), skin temperature (Tsk) and shot accuracy (SA) after performing high intensity exercise at 22 °C and 38 °C and relative humidities of 31% and 38% respectively. Study 1 compared Tre, Tsk, SA in a temperate environment (TE) and a hot environment (HOT). HOT trial Tre (38.5 ± 0.4 °C) and Tsk (35.0 ± 1.6 °C) were higher than TE (37.8 ± 0.7 °C and 32.0 ± 1.3 °C, respectively). SA decreased (p = 0.003) between TE [57.5 ± 17.9 au out of 100] and HOT (33.4 ± 4.0 au), with greatest reduction in players with highest scores. Study 2 examined cooling of abdominal walls and thighs during rest periods and recovery on Tre, SA. Tre increased between start and end of both trials (p < 0.008). Treatments didn’t mitigate increased Tre. Treatment SA increased (p < 0.05). Study 3 evaluated continuous cooling device (vest) plus ice-pack applications on thighs, during rest periods in the high intensity protocol and recovery in hot condition verses control on Tre, SA. A significant time by condition effect for Tre (p < 0.05). Tre at end of high intensity protocol in control was 38.3 ± 0.6 °C. Tre at end recovery in control was 38.4 ± 0.4 ° C. No difference between Tre at start of treatment condition (37.5 ± 0.6 °C) and end of high intensity exercise (38.0 ± 0.7 °C). Tre at the end of recovery (37.0 ± 1.4 °C) was lower than Tre at end of high intensity exercise (p < 0.008). Tre at the end of recovery in control was higher than Tre at end of recovery in treatment. SA increased in treatment condition versus control [(p < 0.05) and large effect size (Cohen’s d = 1.38)]. Combined cooling mitigated the rise of Tre and increased SA in elite tennis athletes.