The influence of applied temperatures has been evaluated on the creep rupture life of a third-generation low-cost single crystal (SX) superalloy with Pt-Al coating. The damage was observed at 1100°C, 1120°C, and 1140°C under the applied stress of 137 MPa. The bare high-temperature alloy outperforms the superalloy with coating in all test parameters. The most significant reduction in creep life up to 50 % occurs when tested at 1100°C/137 MPa. Increasing the temperature from 1100°C to 1140°C improved Creep life of coated superalloys and minimized the reduction to 20% as compared to the bare superalloy. At higher temperatures (1120°C and 1140°C), sluggish crack propagation in Pt-Al coatings to SX superalloy substrate, reducing mechanical property degradation. Oxidation of coating crack tips and Al diffusion into coating cracks to form oxides, rather than penetration into the SX substrate, cause microstructures in the substrate beneath the layer to degrade slowly. At 1100°C, however, the coating/SX substrate microstructure degraded due to the Al internal diffusion. This diffusion mechanism governs the formation of harmful TCP phases at around 1100°C. Therefore, the microstructure stability of coated alloys at 1120°C and 1140°C is better than that at 1100°C. The TEM results revealed that at 1120°C and 1140°C, the dislocation of the SX substrate beneath the coating remained relatively unchanged compared to that in the inner superalloy. In contrast, the dislocation network of the substrate beneath the coating became sparse, and the number of superdislocations cutting into ?? phases increased at 1100°C. This change further intensified the mechanical property degradation of the coat on the SX superalloy. This study aims to provide guidance on appropriate service conditions for high-temperature protective coatings, enabling the development of more advanced coatings.