STAR Greater Western Sydney defender Zac Williams sits comfortably alongside his higher profile teammates, even if he took a far different path to the AFL than most of them.

Among the host of top-10 draft picks the Giants have on their list, Williams is the poster boy of the GWS Academy system, and the club's best rookie list success story.

The Giants' final selection in the seventh round of the 2012 NAB AFL rookie draft, Williams became the club's first Academy product to make his senior debut against Gold Coast in round five the following year.

When he breaks through the banner in Saturday night's semi-final against Brisbane at the Gabba, Williams will also be the first Academy player to reach the 100-game milestone.

The boy from Narrandera in country New South Wales took some time to establish himself as a Giants regular, but his now regarded as one of the League's finest small defenders.

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"It took me three years, I was in and out of the side or I'd be the sub and wouldn't play much," he said this week.

"Leon always referred to it as my apprenticeship in those early days, so it took a while to crack into the side and play regularly.

"I never thought I'd play 50 games let alone 100, but I haven't had time to reflect on the milestone yet just because it's finals time."

Williams is one of the Giants' best attacking half-backs where his willingness to run and carry with the footy makes him invaluable from his defensive half.

However, there could be a chance he'll need to curb some of that offensive flair against the Lions, should coach Leon Cameron decide he's the man to try and shut down gun goalkicker Charlie Cameron.

"If Leon wants me to go and play on him I'm sure we'll have a bit of a giggle because I know him pretty well, there'll be a bit of banter flying around," he said.

"I've spent some time with him at indigenous camps over the years and when he was at Adelaide we were both pretty young then, and we played on each other a lot.

"He's just so talented and spent a few years under Eddie Betts learning the tricks of the trade.

"I love playing on Charlie and I think he loves playing on me."

The two teams had contrasting results in week one of the finals, with the Giants crushing the Western Bulldogs at home, and Brisbane falling to Richmond at the Gabba.

Williams knows last week means nothing when the ball is bounced in Saturday's semi-final, and he's ready for the Lions to respond to their disappointing 47-point defeat, their second in a row to the Tigers after they also lost in round 23 at the MCG. 

"Richmond ended up running over the top of them but I think Brisbane actually played a really good game," he said.

"They were a bit unlucky and missed a few goals early, but they finished top two for a reason, they're the real deal.

"They've had a great year and they're going to come out firing.

"The Lions are a really quick team and really skillful, and they have a lot of talented young boys who crack in hard."

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