Selwood had 28 possessions including seven clearances and eight inside 50s as his team overcame some woefully inaccurate kicking for goal to win 8.17 (65) to 9.8 (62) in front of 81,691 fans.
Geelong dominated for large periods but trailed for much of the match after kicking 2.9 in the opening quarter.
Behind by five points at three-quarter time, Chris Scott's men found their range in the final quarter, kicking three quick goals between the 12 and 18-minute mark to open up a 10-point lead.
A Dale Thomas snap as the clock ticked into time on put the Magpies back within striking distance, but Geelong held on to inflict Collingwood's first defeat since round 22 last season and move a game clear at the top of the ladder.
Joel Corey was the leading possession-winner on the ground with 31, while Jimmy Bartel was the Cats' only multiple goal-kicker with two.
Dane Swan had 30 touches and kicked a goal for the Magpies to be their most influential player, with Steele Sidebottom and Travis Cloke both booting two goals.
Where it was won
Geelong looked in trouble when behind by 17 points midway through the third quarter, but showed typical determination to regain the ascendency.
Collingwood managed just one inside 50 in the last 11 minutes of the quarter as the Cats, through Bartel and fifth-gamer Allen Christensen, kicked the last two goals before the final change, taking momentum to the huddle.
Where it was (almost) lost
The Cats brought back memories of their 2008 Grand Final loss to Hawthorn with some dreadful attempts at goal in the first half.
Geelong's ferocious tackling pressure had Collingwood looking flat early, and the ball spent most of the first quarter in the Cats' forward 50.
But the Cats had eight behinds on the board before Mathew Stokes finally booted their first goal at the 26-minute mark, with Selwood, Daniel Menzel, James Podsiadly and Steve Johnson all missing gettable shots.
Collingwood found some spark in the second term and hit the front at the 12-minute mark, but Geelong once again didn't help itself.
Mitch Duncan, Cameron Ling and Podsiadly all sprayed set shots out on the full as Scott's team kicked just one behind for the quarter to enter the main break 11 points down.
Influential players
Selwood started red-hot with 10 first quarter disposals, setting the early tone for his team.
With the game up for grabs in the frantic final 30 minutes, it was Corey who stepped up, gathering 11 fourth-quarter disposals and driving the ball inside 50 six times.
Magic moment
Collingwood was 10 points in front 12 minutes into the final term when Heath Shaw launched a clearing kick out of defence towards his star teammate Swan.
But the gun onballer was beaten in a one-on-one contest by impressive youngster Menzel, who drove a long ball back inside 50.
Selwood took a strong contested mark deep in the forward pocket and handballed over the top to Johnson in the square, who banged the ball home to the delight of Cats fans.
The goal sparked two more quick ones for the Cats as they built what eventually proved to be a match-winning lead.
Not tough?
"Footy isn't tough anymore," was a popular catchcry among fans this week after Melbourne's Jack Trengove was suspended for a rough tackle.
Try telling that to Alan Toovey.
The Magpies half-back showed incredible courage in backing into a pack during the third quarter, and crashed to the ground after being collected at full speed by the knee of a flying Tom Hawkins.
Play was held up for several minutes as the concussed backman was stretchered from the field and taken to hospital with suspected face and chest injuries.
The controversy
Collingwood was two points down in the dying minutes of the game when ruckman Cameron Wood won a free kick on the half-forward flank.
Scott Pendlebury picked the ball up and kicked a running goal that Magpies fans and players were sure had put their team in the lead.
But the umpire had lost sight of the ball and blown time-on, so the goal was disallowed.
Collingwood coach Mick Malthouse was unimpressed after the match.
"Clearly to me it was an advantage," he said.
"What we've been told is that players make up their mind.
"We went, Geelong went, we kicked a goal, it comes back.
"So someone's clearly got it wrong. Us, them or whatever."
What it means
It means the premiership race is well and truly on.
The Cats have stamped themselves as Collingwood's equals, and any thoughts Magpies fans had of waltzing unchallenged to back-to-back flags are out the window.
It also means Adelaide could be in for a torrid time at Etihad Stadium next Saturday against a Magpies team not used to losing.
Malthouse said his men looked like "crusty, stale, old players" during the first quarter. Expect a brutal response.
Toyota AFL Dream Team highlight
Geelong: Steve Johnson played an excellent game, picking up 25 disposals, eight marks, nine tackles and a goal for 127 Dream Team points - the most on the ground.
Collingwood: Heath Shaw was a popular trade replacement for the injured Jack Grimes this week and he rewarded those who took him with 124 points.
The next four
Geelong: Another big Friday night showdown looms next week against Carlton, before the much-anticipated first meeting with Gary Ablett and the Gold Coast Suns. Then it's the Western Bulldogs and Hawthorn.
Collingwood: A rare home game at Etihad Stadium against Adelaide next week, followed by clashes with the West Coast Eagles, St Kilda and Melbourne.
What the coaches said
Chris Scott (Geelong)
“We were getting the shots, the game was being played up in our forward half, we thought we were dominating the game and quality players tend to turn around those skill errors very quickly. I am not sure we turned it around completely … but the pleasing thing is we were getting the shots and we were playing the way that we want to play, expect for the goal kicking.”
Mick Malthouse (Collingwood)
“We lost our structure. When you lose your structure in today's football, you lose control of your own destiny, and it was all played in Geelong's front half.”
Geelong 2.9 2.10 5.12 8.17 (65)
Collingwood 1.1 5.3 7.5 9.8 (62)
GOALS
Geelong: Bartel 2, Varcoe, Kelly, Johnson, Stokes, Christensen, Podsiadly
Collingwood: Sidebottom 2, Cloke 2, Krakouer, Pendlebury, Thomas, Brown, Swan
BEST
Geelong: Selwood, Ottens, Kelly, Scarlett, Corey, Menzel
Collingwood: Thomas, Swan, Sidebottom, Shaw, Buckley
INJURIES
Geelong: Darren Milburn (back) replaced in selected side by Allen Christensen, Cameron Ling (shoulder)
Collingwood: Nick Maxwell (foot) replaced in selected side by Tyson Goldsack, Alan Toovey (face)
SUBSTITUTES
Geelong: Cameron Ling (shoulder) replaced by Allen Christensen in the third quarter
Collingwood: Alan Toovey (face) replaced by Brad Dick in the third quarter
Reports: Nil
Umpires: Chamberlain, Ryan, Jeffery
Official crowd: 81,691 at the MCG
The views in this article are those of the author and not necessarily of the clubs or the AFL.
