West Coast coach Andrew McQualter has described the club's second 100-point defeat in four weeks as "devastating", admitting the Eagles have gone backwards in the past month.

After a rousing comeback win on the road against Port Adelaide in round three, West Coast have crashed back down to earth with an average losing margin of 82.75 points through four games.

The latest capitulation was a 101-point smashing to St Kilda on Sunday, when they conceded eight unanswered goals in the last quarter.

"Our game's gone backwards in the last few weeks, that's evident for all to see," McQualter said.

"We're getting a pretty clear formula on what we need to do in our game to be able to be competitive, and that's around our defence and our pressure on the ball and our ability to stop teams taking marks.

"This is a big loss, and it's devastating for our fans, for us, for everyone involved.

"Scoreboard aside, we're not playing the way we want at the moment, which is the most disappointing part.

"We think we've got some things that we can adjust that will help a little bit, but the road ahead is going to be long and tough, and we're embracing that challenge."

There were few highlights for the Eagles, whose one win in 2025 came against St Kilda.

But prized No.1 draft pick Willem Duursma earned his coach's praise for undertaking a tagging job on St Kilda supremo Nasiah Wanganeen-Milera, even if his opponent tallied 34 possessions.

"He's going to learn so much from one of the best players in the competition," McQualter said of Duursma.

"He embraced that challenge. He asked to do it.

"If that's the mindset of our highest draft pick and one of our youngest players on our list, there's a fair bit that can go through the group."

West Coast return home for a winnable game next Saturday when they face Richmond at Optus Stadium.