We compute Luscher corrections for a giant magnon in the eta-deformed (AdS(5) x S-5)eta using the su(2 vertical bar 2)q-invariant S-matrix at strong coupling and compare with the finite-size effect of the corresponding string state, derived previously. We find that these two results match and confirm that the su(2 vertical bar 2)q-invariant S-matrix is describing world-sheet excitations of the eta-deformed background. (C) 2017 The Author(s). Published by Elsevier B.V.