Urahara did not expect him to ignore the blade entirely... Maybe the blade didn't really harm him? It certainly didn't make much of a dent the first time he tried. Caught off guard, the punch made contact. He felt the wind being knocked out of him as he doubled over, flying backwards with the force.
Crashing to the ground, he recovered and scooped himself up to a crouched position, watching Grunt. He smiled slightly. "Well done"