  We study explicitly the applicability of perturbative QCD (pQCD) to the pion
virtual Compton scattering. It is found that there are central-region
singularities introduced by the QCD running coupling constant, in addition to
the end-point singularities generally existed in other exclusive processes such
as the pion form factor. We introduce a simple technique to evaluate the
contributions from these singularities, so that we can arrive at a judgement
that these contributions will be unharmful to the applicability of pQCD at
certain energy scale, i.e., the ``work point'' which is defined to determine
when pQCD is applicable to exclusive processes. The applicability of pQCD for
different pion distribution amplitudes are explored in detail. We show that
pQCD begins to work at 10 ${GeV}^2$. If we relax our constraint to a weak
sense, the work point may be as low as 4 ${GeV}^2$.
