Rodolphus was beginning to enjoy the adrenaline rush surging through his body. He knew not to drop his guard while his opponent was still on his feet. The boulder coming at him was typical and with a flick of the wand he exploded it. Unfortunately the force of the following spell caught up some of the fragments causing the slashing spell to hit a bit harder than it would have on it's own. His arm, which he'd raised to protect his face, took the brunt of the hit and blood now dripped from the cut in his arm.
With a sweep of his wand, Rodolphus lifted the rock fragments that remained and sent them flying toward Potter followed by a leg locking hex.