Graphene coatings have sprung up as promising solid lubrication materials due to their intriguing mechanical properties. Achieving in situ deposition of a conformally encapsulated, high-quality graphene coating on hard substrates holds immense potential for industrial antifriction applications. However, the challenge persists in ensuring robust adhesion between graphene coatings and hard substrates (WC-Co), while minimizing excessive interfacial bonding to reduce growth energy consumption and friction. To tackle this problem, NiCo solid solution and competitive reaction strategies have been employed to achieve the in situ self-adaptive growth of graphene coating on WC-Co substrates with intimate interfaces. The high-temperature solid solution breaks through the physical diffusion barriers of the Co binding phase within the substrate to the Ni layer, facilitating the strong coupling effect at the NiCo-WC substrates. Experiments and density functional theory demonstrated that the accumulated Co atoms induce competitive reactions to inhibit the overlap of the electron cloud in Ni-C bonds, providing C atoms with sufficient energy to in situ segregate and diffuse laterally. Benefiting from the weakened interfacial covalent interaction and lower sliding energy barrier, graphene coating in situ deposited on substrates with deeper NiCo solid solution demonstrates superior macroscale low-friction and durability. Drawing on this design strategy, it is highly expected that hard substrate can be extended to diverse industrial surfaces composed of competitive metals for engineered graphene anti-friction applications.