The Magpies led by 15 points after an impressive opening term on Friday night, but the loss of star duo Jordan De Goey and Jeremy Howe to injury proved costly.

De Goey was subbed out of the game after copping an accidental hip to the face from Eagles midfielder Tim Kelly in the first quarter.

Blood streamed out of De Goey's broken nose as he was assisted off the ground, and although he made a brief return, he was later diagnosed with concussion.

"More than likely he misses another week," Collingwood coach Nathan Buckley said.

"I don't think he'll miss any more than that with his nose, but he won't be able to play next week given the (concussion) rules."

Howe appears set for a sizeable stint on the sidelines after injuring his right hamstring in a marking contest during the second term.

The 30-year-old immediately grabbed on the upper part of his right hamstring after landing, and he could barely bend his leg as he was helped off the ground.

Darling was unstoppable during the second quarter, booting three goals from strong marks and another major after catching speedy defender Isaac Quaynor holding the ball.

His efforts helped propel West Coast to a 12-point lead by halftime, and they put Collingwood to the sword in the third quarter to run away with the 16.7 (103) to 11.10 (76) win in front of 54,159 fans.

Darling finished with 5.1 from 15 disposals, while Oscar Allen was also critical with five goals and four contested marks in arguably his best game at AFL level.

Midfielder Dom Sheed iced the game late in the third quarter with three goals in the space of two minutes, while Jeremy McGovern was brilliant in defence.

"Jack stood up, Dom had a little period of brilliance there, and I thought McGovern was our best player," Eagles coach Adam Simpson said.

Buckley rolled the dice by sending defender Darcy Moore into attack, and the All-Australian finished with three goals and eight marks from nine disposals.

Moore had four disposals and a goal in the opening term, but his next possession didn't come until the 10-minute mark of the fourth quarter when he booted his second goal.

The injuries to De Goey and Howe come at a bad time for the Magpies, who are now 1-4 and are also without star midfielder Taylor Adams for at least another nine weeks.

West Coast suffered their own major blow during the week when Liam Ryan was cut down by a stress reaction in his shin that could sideline him for up to eight weeks.

Defender Tom Cole suffered a horrific clash of heads with teammate Josh Rotham late in Friday's match but Simpson is optimistic there wasn't a concussion.

Collingwood bucked the odds to beat West Coast by one point in last year's elimination final in Perth, and their spirited opening quarter would have given their fans hope for a repeat result.

Ruckman Brodie Grundy drifted forward to boot two goals from two strong marks, while Moore added one himself to give the Magpies the momentum.

But the game turned dramatically from that point on courtesy of Darling's second-quarter rampage.

And with Allen also plucking a series of strong grabs, Collingwood's defence wilted.

The margin blew out to 41 points at the final change, with a three-goal fightback from Collingwood early in the last quarter proving too little, too late.

Australian Associated Press