The Magpies looked set for an easy victory after opening a 34-point lead late in the third quarter of Sunday's match in front of 47,609 fans at Optus Stadium.
But the Eagles, led by a hobbled Harley Reid, twice closed to within 10 points in a frantic final quarter that featured plenty of heroic acts from both sides.
Collingwood held their nerve more often than not to seal the 17.15 (117) to 15.8 (98) win, with the result securing the Magpies (12-8-1) a berth in the AFL's new wildcard round.
Despite dealing with the close attention of tagger Brady Hough, Daicos tallied a whopping 39 disposals, 10 clearances, 12 score involvements, 722m gained, two goal assists and a goal to further tighten his grip on the Brownlow Medal.
"He just drags players with him at times," Collingwood coach Craig McRae said of Daicos.
"And his work rate's enormous. Young people watching at home today, or watching live, would have seen how hard he works.
"His game's gone another level, and he takes us to places that we want to get to."
West Coast coach Andrew McQualter was also in awe of Daicos.
"He's extraordinary," McQualter said.
"In my opinion, he's the best player in the competition by a long stretch. I don't think there's anyone close to him at the moment."
Josh Daicos was also instrumental with 35 disposals and a game-high 884m gained.
While the Daicos brothers were shining, West Coast's star midfielder Reid was hampered from the moment he sustained a huge hit to a quad in the first quarter.
The 21-year-old bravely battled through the painful cork to finish with 30 disposals, six clearances and a goal.
Reid was particularly crucial in West Coast's fightback, and he received plenty of help from Elliot Yeo (28 disposals, 11 clearances, one goal) and Jake Waterman (three goals).
Lachie Schultz, Tim Membrey and Daniel McStay kicked three goals apiece for Collingwood, who entered the match missing Scott Pendlebury, Jordan De Goey, Jeremy Howe, Harry Perryman and Patrick Lipinski from the team that lost to Geelong by 25 points last week.
West Coast (4-17) have now lost nine games on the trot, but their effort against Collingwood was full of spirit.
The opening quarter was an entertaining shootout as both sides kicked six goals.
West Coast's accurate return of 6.1 - with the only blemish a rushed behind - came in stark contrast to their loss against Richmond a week earlier when they had 3.17 to their name midway through the third term.
Yeo's 50m running goal with just seconds left in the quarter sent the crowd wild, and the Eagles opened an 11-point lead midway through the second term when Jack Graham kicked truly on the run.
A long bomb by Nick Daicos helped spark a three-goal run by the Magpies, helping the visitors enter halftime with a six-point advantage.
The major highlight of the second quarter was a bone-crunching but fair hit by Eagles defender Brandon Starcevich on Ed Allan, with both players unscathed.
Nick Daicos racked up 21 disposals, five clearances, one goal and a goal assist in a monster first half, and he continued to dominate in the third term as Collingwood broke the game open.
