Bab 107: Chapter 107 - Weird symbol

It wasn't that he was saying that he was the greatest fighter. But still before this match you can say that almost every S-grade elves were afraid of him, but why did this elf gain sudden confidence? It is really a mystery to him. 

But he did not think that much about that and completely focused on this fight. When the referee gives them the signal to fight, both of the fighters completely vanish from their place. Instantly a clash happened between Alex and that elf warrior. Because of that a huge impact was also created that sent both of the warriors backward. 

Well you should understand that from the start Alex was only using the power of a S-grade fighter. Because of this you can say that he did not instantly win this match. But suddenly he becomes surprised after realizing that somehow that elf fighter who just came to the battle ring suddenly has this much power. It wasn't that this cannot happen but he was just surprised.