The support for the Dockers has swelled significantly, with West Coast fans parochially throwing their support behind their cross-town rival.

There is still a feeling on the west coast that the AFL is nothing other than an expanded VFL competition in disguise. It's us against them, once our side is out of the race!

Even Fremantle forward Matt de Boer has noticed the extra pats on the back this week. ''It's great for our fans and supporters; everyone's getting on board,'' he said.

''I think we're even converting a few of the Eagles supporters over as well. It's good for WA football.''

If there are nerves in Fremantle - if the trees, clad in purple and white, lining the cafe strips in the town, and the purple buses driving past belting out the team song are getting to them - they are doing a great job of hiding it.

For de Boer, being supported by the Eagles faithful may even feel a bit nice, seeing as he was a West Coast supporter before he was drafted to Fremantle.

The last time the Dockers played in a preliminary final, in 2006 against the Swans, he would probably even have been wearing a yellow and blue jumper while watching the clash.

''I was still in high school, so was 'Fyfey' [teammate Nat Fyfe],'' he said.

It's also de Boer's 100th AFL game on Saturday night and that too has taken a back seat in the lead-up to the game. He was recruited in the 2009 rookie draft and elevated to the senior list before the start of the season.

But he isn't thinking too much about that right now, in his own words, ''we have bigger fish to fry''.

''[The Swans] are an elite team and they are the reigning premiers for a reason. You can't write Sydney off - you do that at your own peril.''

That's good advice. Even the Dockers' home record of 16 wins in 17 games can't be talked about in too much context for this game. Fremantle put paid to that when it beat Geelong in the first week of the finals to end the Cats' brilliant run of victories at their Simonds Stadium base.

And the teams that will fight for a spot in the grand final are significantly different to those that battled it out at the same time in 2006.

Fremantle coach Ross Lyon was an assistant coach at the Swans. Another man who the Dockers have in their corner who was wearing red and white seven years ago could also have an impact on the result - assistant coach Brett Kirk.

He had 28 possessions in the Swans' victory over the Dockers and de Boer admits that his experience in the big games is having an influence on the team in the build-up to this week.

''He's obviously got some more intricate knowledge of them and he's helped feed that through to the boys,'' he said.

''Obviously their game plan has changed a little bit since he's been there, but in terms of knowing the players a little bit, it's definitely been helpful.''