Trailing by 22 points and appearing flat late in the first quarter, the Magpies rediscovered their spark by booting 11 of the next 14 goals to blow the Cats away in front of 78,749 fans on Friday night.
Geelong charged back hard early in the final term, cutting a 24-point margin at three-quarter time to just nine in just minutes, but the Magpies steadied to prevail 16.13 (109) to 15.11 (101).
Star forward Jeremy Cameron threatened to swing the game back in the Cats' favour, incredibly kicking his fifth and sixth goals of the match while standing completely out of bounds as the umpires inexplicably failed to blow the whistle.
But Brody Mihocek was just as impressive at the other end, booting a career-high five goals for Collingwood to bounce back after going goal-less in four of his previous five outings.
Making the result - which all but seals the minor premiership for the Pies (17-4) - more impressive is they did it without Moore.
After losing superstar Nick Daicos for up to six weeks in last week's shock defeat to Hawthorn, Moore being hurt is the last thing the premiership favourites need.
Moore, the potential All-Australian captain, suddenly grabbed for his left hamstring while running late in the first quarter and immediately went to the bench.
The star defender received attention from medical staff in the rooms, and was subbed out of the match for small forward Jack Ginnivan at quarter time.
Magpies football boss Graham Wright described Moore's injury as "hamstring tightness" and the 27-year-old will get scans to determine the damage.
"They tried to loosen him up so couldn't get him going," Wright told the Seven Network.
Collingwood, who have topped the ladder for most of the season, have had few injury concerns this year until the last week when Daicos suffered a hairline fracture in his knee that could keep him out until the preliminary final.
Dynamic midfielder Jordan De Goey sent a further scare through their camp when he came to the bench in pain several times.
But he went back on the ground and ran out the match to finish with 20 disposals.
Geelong were also forced to use their sub in the first half after forward Gary Rohan was struggling with a hip injury.
Cameron was clearly the Cats' most dominant player with seven goals, but their defence regularly fell apart as the Magpies were able to score easily out the back.
Geelong will need to win their remaining two matches against St Kilda (Marvel Stadium) and the Western Bulldogs (GMHBA Stadium) to be any chance of keeping their premiership defence alive and qualify for finals.
The Cats could finish the round as low as 12th on the ladder.
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