WEST Coast coach Adam Simpson says his side must play four-quarter football against Collingwood after switching off in the second half against the Sydney Swans last week.

The Eagles face the Magpies on Sunday afternoon at Domain Stadium coming off a 39-point loss to the Swans.

The Eagles led the Swans nine minutes into the third term before conceding the last six goals of the match through what Simpson described as a series of lapses.

He said it was vital his side maintained their intensity for the entire match against Collingwood.

"(We have to) play four quarters of footy," Simpson said.

"You just don't have the luxury of switching off in any area for too long because you get burnt.

"We were in the game for a long time. But there were just some really critical cough ups that we'd have. We set up pretty well, we gave our forwards opportunity but we were made to pay on the ways that we slipped up. It's just a fine line and you've got to be on all day against Sydney."

Simpson said a couple of players were still sore from the game. Andrew Gaff, Eric Mackenzie and Jeremy McGovern all had light days on the track on Tuesday but that has been a regular occurrence over recent weeks. Simpson said it was highly unlikely that any player would miss through injury given the eight-day break.

Simpson said he was wary of what the Magpies would bring on Sunday following a powerful display against Essendon on Anzac day.

"(It's the) highest score they've kicked in four years," Simpson said.

"They really put pressure on the game, converted.

"They'll come over with a lot of confidence. At stages this year they've been really, really dangerous and their pressure has been pretty good.

"You look at their team and the balance they have across the board, I think they showed what they can do on the weekend."

The Magpies have lost their last four matches in Perth and haven't beaten West Coast at Domain Stadium since 2009.