  We use the two-step density-matrix renormalization group method to elucidate
the long-standing issue of the universality class of the Mott transition in the
Hubbard model in two dimensions. We studied a spatially anisotropic
two-dimensional Hubbard model with a non-perfectly nested Fermi surface at
half-filling. We find that unlike the pure one-dimensional case where there is
no metallic phase, the quasi one-dimensional modeldisplays a genuine
metal-insulator transition at a finite value of the interaction. The critical
exponent of the correlation length is found to be $\nu \approx 1.0$. This
implies that the fermionic Mott transition, belongs to the universality class
of the 2D Ising model. The Mott insulator is the 'ordered' phase whose order
parameter is given by the density of singly occupied sites minus that of holes
and doubly occupied sites.
