  The AGT conjecture claims an equivalence of conformal blocks in 2d CFT and
sums of Nekrasov functions (instantonic sums in 4d SUSY gauge theory). The
conformal blocks can be presented as Dotsenko-Fateev beta-ensembles, hence, the
AGT conjecture implies the equality between Dotsenko-Fateev beta-ensembles and
the Nekrasov functions. In this paper, we prove it in a particular case of
beta=1 (which corresponds to c = 1 at the conformal side and to epsilon_1 +
epsilon_2 = 0 at the gauge theory side) in a very direct way. The central role
is played by representation of the Nekrasov functions through correlators of
characters (Schur polynomials) in the Selberg matrix models. We mostly
concentrate on the case of SU(2) with 4 fundamentals, the extension to other
cases being straightforward. The most obscure part is extending to an arbitrary
beta: for beta \neq 1, the Selberg integrals that we use do not reproduce
single Nekrasov functions, but only sums of them.
