The striker questions the benefit of holding the tournament outside Spain and believes the distance makes it more difficult for supporters to attend.
According to Williams, it hits Athletic Bilbao particularly hard, whose support is largely local, unlike bigger clubs such as Barcelona and Real Madrid.
"Playing in Saudi Arabia is shit," Williams told Marca.
This year's edition of the Super Cup will also be particularly emotional for the Bilbao captain. He is expected to become a father for the first time in the same week the tournament is decided.
"It hurts to leave my wife and son," he said and continued:
"But I am available for the club and will try to make the best possible Super Cup."
Athletic Bilbao will face Barcelona in one semi-final on January 7. In the other, Real Madrid and Atlético Madrid will compete for the final spot.
