The tendency to perceive an outcome that has occurred as being obvious and predictable and is called the

I believe the answer is: hindsight bias

an example of an hindsight bias would be when a supporter of a certain fighter react when he deliver a knockout blow to an equally strong opponent and say

'see, i told you he can win this easily'

Even though his statement might appear to be true, there he would not be able to provide objective evidence on his statement since the opponent could very much do the same on different fight.