We study the heavy quark/antiquark pair dynamics in strongly-coupled quark gluon plasma. A semi-classical approach, based on the Wigner distribution and Langevin dynamics, is applied to a color screened $c{\bar c}$ pair, in a hydrodynamically cooling fireball, to evaluate the total $J/\psi$ suppression at both RHIC and LHC energies. Although its limitation is observed, this approach results to a $J/\psi$ suppression of around 0.30 at RHIC and 0.25 at LHC.