  We reduce the perturbative uncertainty in the determination of |V_{ub}| from
inclusive semileptonic B decays by calculating the rate of B -> X_u l nu events
with dilepton invariant mass q^2>(M_B-M_D)^2 at subleading order in the hybrid
expansion, and to next-to-leading order in renormalization-group improved
perturbation theory. We also resum logarithmic corrections to the leading
power-suppressed contributions. Studying the effect of different b-quark mass
definitions we find that the branching ratio after the cut is Br(B -> X_u l
nu)=(20.9+-4.0)|V_{ub}|^2, where the dominant error is due to the uncertainty
in the b-quark mass. This implies that |V_{ub}| can be determined with a
precision of about 10%.
