  The superconducting state formed due to direct intra-orbital pairing in
tetragonal multi-band superconductor Sr$_2$RuO$_4$ has different properties
than the state formed due to intra-band pairing. In particular, the theory
operating with direct intra-orbital pairing successfully explains the Kerr
rotation of reflected light polarization observed several years ago. Here we
apply intra-orbital approach to the problem of Ginzburg-Landau description of
basal plane upper critical field in this material. It is shown that typical for
two component superconducting state additional phase transition in the vortex
state at $H<H_{c2}$ for all four crystallographic directions of magnetic field
in the basal plane and the basal plane upper critical field anisotropy still
are inevitable properties even in case of direct intra-orbital pairing.
