The visitors led at every change and dominated the inside-50 count 66-52, but the Pies ran out 17.7 (109) to 15.11 (101) victors.
Simpson couldn't fault his side's effort, but rued the Eagles' inability to find another gear to halt the Magpies' fourth-quarter charge.
Roared home by their black and white army, Collingwood kicked four of the last six goals.
Five talking points: Collingwood v West Coast
It was another heart-breaking defeat in Melbourne for the Eagles after they let a four-goal lead slip in the final term against Carlton at Etihad Stadium in round six.
"Our endeavour and intent were there, we just couldn't sustain it in that last 15 minutes," Simpson said post-match.
"There was critical moments in the last quarter where their class with their midfielders and their forwards and their defence held up.
"So I thought rather than us dropping off I reckon they might have elevated to another level.
"We missed an opportunity, I wouldn't say it's the one that got away. I thought the Carlton game maybe was."
West Coast was at long odds to upset the Pies and had a woeful record to overcome of one win against Collingwood in 10 games at the MCG.
The Eagles looked shaky as Collingwood slotted the game's opening two goals, but wrestled back the initiative through their midfield - particularly Matt Priddis (35 disposals, two goals), Andrew Gaff (26 disposals, nine marks), Scott Selwood (26 disposals, five tackles) and ruckman Nic Naitanui.
"We're happy that we're seeing signs of improvement. We're definitely seeing some good signs," he said.
"I thought our midfield as a collective stood up for the most part of the day. We had 66 inside-50s, so the supply was there, we just couldn't capitalise. Their defenders actually were really good.
"We've been craving for that type of supply in bigger games and we got it today.
"I normally back our forwards in. It's one of our strengths as a club, so not often do we get that supply and not convert."
Just days after inking a five-year contract extension Naitanui showed desire that has often been questioned as he gathered 17 touches, with three tackles, five clearances and 24 hit-outs.
While it was a much-improved display, Naitanui never delivered on his threat to break the game open and couldn't hold any of the high marks he flew for.
"He's just so close isn't he to taking some of those marks, but what he did do is provide a contest," Simpson said.
"We would have got two or three goals from the crumbs and from the carnage he caused.
"There's still obviously another gear he can go to, but like I've been saying all year we're seeing small improvements weekly."
West Coast still hasn't beaten a finals contender this season and has now slumped to 4-5 with a vital home match against North Melbourne to come in round 11.
Twitter: @TravKing_AFL
It was another heart-breaking defeat in Melbourne for the Eagles after they let a four-goal lead slip in the final term against Carlton at Etihad Stadium in round six.
"Our endeavour and intent were there, we just couldn't sustain it in that last 15 minutes," Simpson said post-match.
"There was critical moments in the last quarter where their class with their midfielders and their forwards and their defence held up.
"So I thought rather than us dropping off I reckon they might have elevated to another level.
"We missed an opportunity, I wouldn't say it's the one that got away. I thought the Carlton game maybe was."
West Coast was at long odds to upset the Pies and had a woeful record to overcome of one win against Collingwood in 10 games at the MCG.
The Eagles looked shaky as Collingwood slotted the game's opening two goals, but wrestled back the initiative through their midfield - particularly Matt Priddis (35 disposals, two goals), Andrew Gaff (26 disposals, nine marks), Scott Selwood (26 disposals, five tackles) and ruckman Nic Naitanui.
"We're happy that we're seeing signs of improvement. We're definitely seeing some good signs," he said.
"I thought our midfield as a collective stood up for the most part of the day. We had 66 inside-50s, so the supply was there, we just couldn't capitalise. Their defenders actually were really good.
"We've been craving for that type of supply in bigger games and we got it today.
"I normally back our forwards in. It's one of our strengths as a club, so not often do we get that supply and not convert."
Just days after inking a five-year contract extension Naitanui showed desire that has often been questioned as he gathered 17 touches, with three tackles, five clearances and 24 hit-outs.
While it was a much-improved display, Naitanui never delivered on his threat to break the game open and couldn't hold any of the high marks he flew for.
"He's just so close isn't he to taking some of those marks, but what he did do is provide a contest," Simpson said.
"We would have got two or three goals from the crumbs and from the carnage he caused.
"There's still obviously another gear he can go to, but like I've been saying all year we're seeing small improvements weekly."
West Coast still hasn't beaten a finals contender this season and has now slumped to 4-5 with a vital home match against North Melbourne to come in round 11.
Twitter: @TravKing_AFL
