This study aims to investigate the fundamental deformation mechanism of Ti-based bulk metallic glass under mechanical loading by a cutting tip. The cutting tip interaction is resolved into two separate actions, namely nanoindentation by using a Berkovich diamond indenter and contact sliding under a pin-on-disk configuration. The deformation details in the specimens due to the action of the corresponding mechanical loading were analyzed by SEM and TEM. It was found that under nanoindentation, the plastic deformation is evidenced by a series of pop-ins in load–displacement graphs. The temperature rise at the contact interface during sliding must have been above the glass transition temperature and the onset temperature of crystallization, leading to the formation of discrete nanocrystalline particles in the immediate subsurface and hence bringing about an increase in hardness of the metallic glass in the wear tracks.