West Coast’s midfield was “beaten up” in Saturday’s 20-point loss to a more desperate St Kilda outfit at Marvel Stadium, according to coach Adam Simpson.

In a shocking second half performance, the Eagles coughed up a 33-point lead to the rampant Saints, whose pressure and intensity rose to a level the visitors couldn’t handle under the roof.

St Kilda booted eight unanswered goals to snatch victory in a tough result to take in gun defender Brad Sheppard’s 200th game.

The defeat leaves the Eagles in the middle of the pack at 2-2 after four rounds with a six-day break to lick their wounds before facing Collingwood at Optus Stadium on Friday night.

“We played some pretty good footy in the first half. We thought St Kilda’s pressure was there all night. It elevated in the second half and we couldn’t handle it,” Simpson said post-match.

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“We got beaten up in the midfield and we couldn’t stop momentum with the contest.

“That forced us into fumbles and poor decisions and they capitalised, and we just couldn’t get momentum back.

“They were more desperate than we were, obviously.

“When the game was right at that point where we could’ve put the hammer down, I think the belief was still there for the Saints – it was there all day – and they showed tremendous heart.

“And we couldn’t stop it.”

The Saints were always in the contest, but the Eagles’ efficiency going inside 50 was the difference early.

However, St Kilda’s midfield dominance eventually told and Brett Ratten’s side finished well ahead in terms of disposals (+89), contested possessions (+23), inside 50s (+17) and clearances (+15).

Without skipper Luke Shuey (hamstring) and Elliot Yeo (groin), the Eagles’ engine room lacked drive and losing former captain Shannon Hurn (calf) in the opening term of his club record-equalling 290th game ultimately proved costly.

“He’s done a little calf, a little soleus. We’ll get a scan. Soleus’ aren’t terrible but they probably rule you out for a week or two,” Simpson said.

Hurn’s injury handed medical sub Isiah Winder a debut, with the Peel product’s first goal and Jack Petruccelle’s career-best game among only a few highlights for West Coast.

“(Winder) kicked a goal, which is great. Losing a defender early, had to move the magnets around a little bit,” Simpson said.

“Unfortunately for all of our forwards in the second half I think we had 13 inside 50s. They’re not completely bereft of being blamed as well – I think our contest centre-forward was poor.”