In this paper we consider the regularity problem of the Navier–Stokes equations in $$ {\mathbb {R}}^{3} $$
. We show that the Serrin-type condition imposed on one component of the velocity $$ u_3\in L^p(0,T; L^q({\mathbb {R}}^{3} ))$$
with $$ \frac{2}{p}+ \frac{3}{q} <1$$
, $$ 3