Purpose: Automobile racing is physically challenging, but there is no information related to experience level and physiological responses to racing. The aim of this study was to compare physiological responses of professional (PRO) and amateur (AM) sportscar drivers. Methods: Four male racing drivers (PRO n = 2, AM n = 2), completed a physical fitness assessment and had heart rate (HR), breathing rate 10 (BR), skin temperature (T[subscript sk]), core temperature (T[subscript core]), physiological strain index (PSI) and blood glucose (BG) measured continuously during six races. Rate of perceived exertion (RPE), blood lactate, and fluid loss were measured post-race. Results: AM had higher HR compared to PRO during driver changes (AM: 177 ± 12 beats·min[superscript -1], PRO: 141 ± 16 beats·min[superscript -1], p < 0.0001), pit stops (AM: 139 ± 14 beats·min[superscript -1], PRO: 122 ± 1 beats·min[superscript -1], p = 0.0381) and cautions (AM: 144 ± 13 beats·min[superscript -1], PRO: 15 123 ± 11 beats·min[superscript -1], p = 0.0059). During pit stops, PRO (26 ± 6 respirations·min[superscript -1]) displayed a significantly greater BR than AM (AM: 18 ± 7 respirations·min[superscript -1], p = 0.0004). T[subscript core] was greater for PRO (38.4 ± 0.4°C) drivers while in the car during pit stops than AM (36.1 ± 2.5°C, p < 0.0001). AM displayed elevated PSI during cautions (AM: 5.5 ± 1.8, PRO: 3.2 ± 1.3, p < 0.0001) and pit stops (AM: 5.6 ± 1.4, PRO: 2.8 ± 1.1, p < 0.0001). BG was increased for AM versus PRO during pit stops (AM: 20 132.9 ± 20.2 mg·dl[superscript -1], PRO: 106.5 ± 3.5 mg·dl[superscript -1], p = 0.0015) and during racing (AM: 150.9 ± 34.6 mg·dl[superscript -1], PRO: 124.9 ± 16.0 mg·dl[superscript -1], p = 0.0018). AM (3.3 ± 1.7 mmol·dl[superscript -1]) had a higher blood lactate than PRO (1.7 ± 2.6 mmol·dl[superscript -1], p = 0.0491) from pre to post-race. AM (1.90 ± 0.54 kg) lost more fluids over the race than PRO (1.36 ± 0.67 kg, p = 0.0271). Conclusions: Amateur drivers could fatigue faster in the car which results in a decreased driving performance.