The Chiefs midfielder will start his 15th test on Saturday and his first against Ireland with Ma'a Nonu being rested for the first test of the year.
Williams says Nonu won't be happy to give up the jersey.
"I don't think anyone owns any jersey or any position. I don't think if you said to Ma'a to rest him, he'd like the rest. When it comes to the All Blacks we're always battling for that starting jersey, we're always battling for that number 12 and may the best person get the jersey."
The 26-year-old will have plenty of experience around him with first five-eighth Dan Carter starting in his 86th test and centre Conrad Smith playing in his 56th test for the All Blacks.