This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of s√=7TeV and correspond to an integrated luminosity of 4.6fb−1. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum pT>320GeV and pseudorapidity |η|<1.9, is measured to be σW+Z=8.5±1.7 pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques.