Ultrafast energy and phase relaxation of photo-excited electrons has been measured by means of interferometric twophoton time-resolved photoemission with 15 fs pulses. The phase relaxation time for the excitation from the occupied surface state on Cu(111) is found to be ∼20 fs, and is longer than for the excitation from the bulk bands. This makes it possible to demonstrate a coherent control of photo-excited electronic populations with phase-locked pulse pair and chirped pulse excitation.