He said: "Occasions like this are why you play rugby. Everyone has been talking about Australia being the key game of the Rugby World Cup for Wales. Now it is finally here and I want to be part of it."
He also insists this Wales squad is confident especially playing at the Millennium Stadium.
"We are playing at home and we know that at home we are a tough side to beat," said Williams. "We know we have to go up another 20 to 25 per cent from our performance against Canada if we are going to beat Australia. We know the areas where we need to sharpen up but we have played well against Australia in our last two games."
He says training at St Nazaire has been going well with the squad benefiting from a warm welcome off the field: "The training facilities are great and the whole squad is going well so there is a good atmosphere and we are working well in training."