He isn't expecting it, not after the whole 'hit me and feel better' deal. Which is why he isn't even looking at Naruto when he finds himself stumbling backwards, eyes wide with shock before he feels the burning pain in his nose and realises what has happened.

Falling backwards a couple steps before regaining his balance, his fist immediately curls up again, aiming back at Naruto's face once again. A foot also kicks out, aiming to sweep past the other ninja's feet and cause him to fall.