  Analytic continuation of the perturbative series from spacelike to timelike
regions is performed using renormalization group summed perturbation theory
(RGSPT). This method provides an all-order summation of kinematic
``$\pi^2$-terms'' accessible from a given order of a perturbative series. The
impact of the summation of these terms is studied for Higgs boson decay and
electromagnetic R-ratio in the perturbative QCD. Results obtained using RGSPT
have improved convergence behavior in addition to significantly reduced
renormalization scale dependence compared to fixed-order perturbation theory
(FOPT). The higher-order behavior using the Pad\'e approximant is also studied
for processes considered.
