  We develop a manifestly supersymmetric version of the generalized unitarity
cut method for calculating scattering amplitudes in N=4 SYM theory. We
illustrate the power of this method by computing the one-loop n-point NMHV
super-amplitudes. The result confirms two conjectures which we made in
arXiv:0807.1095 [hep-th]. Firstly, we derive the compact, manifestly dual
superconformally covariant form of the NMHV tree amplitudes for arbitrary
number and types of external particles. Secondly, we show that the ratio of the
one-loop NMHV to the MHV amplitude is dual conformal invariant.
