This study proposes a novel approach based on the covalent structure of diamond–graphite–graphene (CDGG) to integrate the outstanding properties of diamond, graphite, and graphene, synergistically improving frictional behavior of fretting interfaces. The results demonstrated that in-situ CDGG significantly reduced the alternating stress at the contact interface, the friction coefficient decreased by 40–62 % over pristine diamond coatings under gross slip regime, accompanied by a shorter running-in period. The counterpart pair wear corresponding to in-situ CDGG was lower, and no delamination caused by metal adhesion. The surface graphene/graphite exhibited good frictional toughness, effectively absorbing the relative displacement at contact interface, enabling CDGG to exhibit partial slip regime under higher loads and smaller displacement amplitudes.