Auckland were beaten 1-0 by Amicale in the OFC qualifying tournament in April and last week battled to a 1-1 draw in the final's first leg.
Which means tomorrow it's all on the line; the OFC crown, the minimum US$500,000 for qualifying and the professional dreams that a Fifa tournament brings.
"A win on Sunday would cap a perfect season, really," said Williams. "I don't want to jinx anything, not that I believe in that kind of stuff, but it would. It would be the first time that a team has gone on to win the charity shield, ASB minor Premiership, Championship and O-League and we also put in a good performance last year in Morocco, despite the loss."
Despite their struggles with Amicale, Williams is confident that Auckland will prove too strong at Kiwitea Street tomorrow.
"This is going to sound terrible but in some ways Amicale are not the toughest side we have faced this year. AS Pirae [who Auckland beat 4-2 on aggregate] were dangerous. I think if we played them 100 times it would be a lot more even spread than if we were to play Amicale.
"But that's not to detract from Amicale, who have only conceded one goal against us in two games. But both of their goals have come from very, very large mistakes from our end. And outside of that they haven't had a lot of very good scoring opportunities. If we can defend the way we're capable of and stop those big mistakes I think they will find it quite hard to score against us."
Williams has also been selected by interim All Whites coach Neil Emblen in the New Zealand squad to face South Africa on May 30. It's been a rapid rise back to the top for the former Football Kingz keeper who only returned to top level football in 2011 after leaving the game for four years as he travelled the world as an international model.
But now, in between juggling a post-grad diploma in zoology, Williams knows what he really wants.
"It's still my dream to play professionally. I have other things that I like to focus on in case it doesn't happen, because I'm not that young any more. But I think the majority of people that pick up some boots and start playing dream of being a pro and I'm still no different."