COLLINGWOOD players were blown away by the noise at Optus Stadium in round 23, but assistant coach Justin Longmuir is confident the Magpies won't be intimidated by a raucous West Coast crowd. 

Former Eagles senior assistant Longmuir was back on his home turf in Perth on Friday, but this time wearing the colours of a bird of a different feather and plotting how to knock off his old club at WA's new sporting mecca.

The Magpies laboured to a nine-point victory over Fremantle to nail down third spot in the final round, getting an invaluable feel for the 60,000-seat stadium, albeit with nearly 20,000 fewer fans than are expected for Saturday night's sold-out qualifying final.

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"The players couldn't believe how loud it was," Longmuir said.

"They got a good look at the stadium, good look at travel routine, so hopefully that puts us in good stead this week. 

"Having known the West Coast supporters, they do get loud and they do cheer their team on, probably no different to any other team.

"We've played in front of some hostile, big crowds this year.

"I wouldn't imagine our players would be intimidated by that."

Longmuir is the Pies' defensive mastermind and has helped Collingwood overcome some crippling injuries to key backmen this season. 

The Magpies have tightened up by two goals a game, with Nathan Buckley's men conceding only 77 points on average this season (AFL No.8).

Longmuir's biggest challenge could be formulating a plan to restrict West Coast stars Josh Kennedy and Jack Darling, although the return of Jeremy Howe and Tyson Goldsack's miraculous comeback from an ACL rupture should help.

"Really conscious of how good they (Kennedy and Darling) are as players, and how good they work together, but we've got to be really careful as a backline group and a team we don't put our effort into solely stopping them," Longmuir said.

"They've got four or five other forwards who have been really dangerous." 

The forecast is for showers in Perth on Saturday afternoon, which could assist the Pies turning the match into a ground-level contest, suiting their fleet-footed and deep midfield division.

West Coast is ranked 18th for groundball gets this season, and Collingwood big man Brodie Grundy could have a major say on proceedings in the ruck, although Longmuir played down talk the Pies would have the engine room edge.

"I don’t know about exploit them. I think our midfield has got a lot of runs on the board this year, our clearance work has been really strong, we've got really good depth in the midfield with Brayden Sier stepping up and performing really well," he said.

"We feel like that's a real strength of ours, but I wouldn't say West Coast's midfield is less strong.

"We need to be on all over the ground.

"We expect, looking at last night's game, there would need to be a bit more contested footy coming into a finals game, so we feel like we've prepared for that."