The combustion relevant elementary reaction of photolytically generated phenyl radicals (C6H5, X(2)A(1)) with molecular oxygen to form the phenoxy radical (C6H5O) plus a ground state oxygen atom was investigated under single collision conditions at a collision energy of 21.2 +/- 0.9 kJ mol(-1). The reaction was found to proceed indirectly via the involvement of a long-lived phenylperoxy radical (C6H5O2) intermediate that decomposed via a rather loose exit transition state. In comparison with crossed beams data obtained previously at elevated collision energies, we suggest that, as the collision energy rises from 21 to 107 kJ mol(-1), the lifetime of the C6H5O2 reaction intermediate decreases, that is, a classical behavior within the osculating complex model.