I dusted him in the game.
I was superior to him in the game.
Probably extension of meaning of dust, as throw dust in the eyes of, mislead, hence be superior. also 'a bout or contest'. (Wright) I'll dust your jacket for you - I'll give you a good beating. The allusion is to dusting carpets, etc. by beating them with a stick. (Brewer) and see 'Dust' - 'The piccolo tune was me dust' - favourite. (Kelleher)