He was taken by surprise. The speed at which his enemy had moved was far too great, and he could not react fast enough. He was not in a state of perception, and so he could not even see where his opponent's attack was coming from. He lost focus on his right hand and the spell failed spectacularly. 

 Cunkuu felt a wave of cold wash over his palm as the fireball exploded, igniting the air right as the hand of Shin landed on his own, fingers becoming interlocked. A wave of incredibly hot air surrounded him, and, in turn, slammed into his opponent, affecting both of them negatively. The younger man was momentarily blinded by the incredible heat and could not enter the appropriate state he would need to enter so that he could react to the speeds of his.