In the framework of the relativistic quantum molecular dynamics approach we investigate antiproton (p\ifmmode\bar\else\textasciimacron\fi{}) observables in Au+Au collisions at 10.7A GeV. The rapidity dependence of the in-plane directed transverse momentum ${\mathbf{p}}_{\mathit{x}}$(y) of p\ifmmode\bar\else\textasciimacron\fi{}'s shows the opposite sign of the nucleon flow, which has indeed recently been discovered at 10.7A GeV by the E877 group. The ``antiflow'' of p\ifmmode\bar\else\textasciimacron\fi{}'s is also predicted at 2A GeV and at 160A GeV and appears at all energies also for \ensuremath{\pi}'s and ${\mathit{K}}^{\mathrm{\ensuremath{-}}}$'s. These predicted p\ifmmode\bar\else\textasciimacron\fi{} anticorrelations are a direct proof of strong p\ifmmode\bar\else\textasciimacron\fi{} annihilation in massive heavy ion reactions.