Triodia pungens is one of the 69 species of an Australian native arid grass which covers approximately 27 % of the Australian landmass. In this study, we report that very long and thin cellulose nanofibrils can readily be isolated from Triodia pungens biomass using unrivalled mild chemical pulping, followed by several mechanical fibrillation methods. After a typical pulping process which includes washing, delignification and bleaching steps, mechanical fibrillation was performed via high pressure homogenization, ultrasonication and high energy ball milling using relatively minimal energy in all approaches. Cellulose nanofibrils with an average diameter of below 10 nm and a length of several microns were obtained. It also has been shown that the nanofibrils obtained from Triodia pungens have a crystallinity index of about 69 %, and a thermal stability of up to 320°C. The sheets produced from high aspect ratio nanofibrils prepared by high pressure homogenization, also demonstrated a very high work at fracture. By evaluating the deconstruction strategies and the performance of nanofibril sheets, we report that the highperformance cellulose nanofibrils can be processed from arid grass bleached pulp with unusually low energy input.