Triple Crown hero Williams aims to make the most of starting spot against Australia.
Triple Crown hero Scott Williams is determined to grab his chance at centre stage on Saturday. (KO 11am UK time)
The Scarlets midfield ace had to contend with a place on the bench during the Six Nations, with Jamie Roberts and Jonathan Davies established as the central axis.
But Williams played a super-sub role and scored the famous match-winning try at Twickenham as Wales clinched the Triple Crown.
Now, with Roberts ruled out with a knee injury, Williams hopes to replicate his Triple Crown form from the outset against Australia.
"I'm just really happy to have the opportunity to start a game," said the 21-year-old. "I've played a lot coming off the bench, with Jamie being in great form.
"This is my opportunity now and I will do my best to try and take it. It's my big chance on the weekend."
Williams, who will win his 13th cap in Brisbane, was selected ahead of James Hook and Ashley Beck. He will form an all-Scarlets midfield with Rhys Priestland at fly-half and Jon Davies at outside centre.
He reckons the familiarity will be a major advantage but insists Wales face a daunting challenge against a wounded
"I think it's an advantage because we've trained and played a lot together," added Williams. "We are used to each other.
"We know we are going to have our work cut out. Australia are not going to be a pushover. They had a really scrappy game against Scotland and were unlucky there.
"But we are just concentrating on what we are taking into the game now. We have got a massive opportunity to put a stamp on a southern hemisphere side."
The Wales Women's team headed to Dare Valley Country Park on a team bonding exercise as the entire squad got together for the very first time in preparation for this season's Six Nations championship which kicks off on Saturday with a clash against defending champions Ireland, in Donnybrook.
Wales Head Coach Warren Gatland discusses his team selection for the opening round of the RBS 6 Nations where he leads his side against Ireland, on Sunday. As WRU TV's Luke Brodley discovers, Gatland is fully aware of the challenges the defending champions pose
WRUTV caught up with Wales Women captain Rachel Taylor at the RBS 6 Nations launch and how a good crowd really helps boost the girls performance. Tickets for all three Women's home games at The Gnoll, Neath are available from www.wru.wales/tickets