The Magpies, who trailed by six points at halftime, blew the Power away after the main break to rack up their fifth win for the season, 17.12 (114) to 11.10 (76).
The result sees the Pies draw level with the Power on points with a 5-5 record, and keeps them in touch with the six other teams vying for a spot in the congested top eight.
It was the first time the Magpies have beaten the Power at the MCG since the preliminary final of 2003, and their second win in a row after beating West Coast at Subiaco Oval last weekend.
Meanwhile, the Power has sunk to two consecutive defeats on the road after being smashed by the Sydney Swans last weekend at the SCG.
In a sterling second half, the Magpies piled on 11 goals to Port Adelaide’s four after upping their intensity and using the ball better than in the first two terms.
Jack Anthony topped the goal-kicking with four, while Brad Dick and Alan Didak were terrific in adding each. Leigh Brown also played his best game since crossing to Collingwood from North Melbourne.
Dane Swan had leather poisoning after collecting 48 possessions, 28 of which came in the first half.
Leon Davis and Kane Cornes engaged in an entertaining battle, as did Scott Pendlebury and Dominic Cassisi, while Simon Prestigiacomo and Warren Tredrea battled in the Port Adelaide attacking 50.
Port Adelaide lost goalsneak Daniel Motlop with an ankle injury before the bounce, and then Chad Cornes for most of the second half, with the veteran spending the remainder of the game on the bench icing his calf and knee.
A power surge at the 12-minute mark of the opening term caused two of the ground's light towers to malfunction, and cut communications between the benches and the coaches' boxes.
Port Adelaide coach Mark Williams headed straight to the ground to coach from the bench, and Collingwood's Mick Malthouse joined him on the sidelines shortly after.
The lights came back on 26 minutes in, but it was the Power that had illuminated the stadium in the absence of electricity to reverse a seven-point deficit into a 13-point lead.
Five individual goal-kickers and big wins in the clearances and inside 50s gave the visitors their advantage, which they held at quarter-time after Tredrea goaled at the 24-minute mark.
Didak kicked his second just two minutes into the next term, which got the Pies back within two straight kicks.
However, the Power snared the next two through late inclusion Matthew Westhoff and Brendon Lade, which put the visitors back out to a 19-point lead.
As the clock ticked into red time, Anthony began to work his way into the game and closed the quarter in style with two goals.
The difference at the main break was six points, with Swan gathering almost double the number of possessions than the next-most prolific player on the ground.
He continued his stellar display with a goal in the first minute of the third term after Nathan Krakouer turned the ball over with a kick-in, which levelled the scores.
From there, the Pies piled on the next six goals before the Power were able to respond. A major to Brad Ebert came their way after Nick Maxwell gave away a free kick, but by then, Port Adelaide was already trailing by 37 points.
Ebert cleverly snapped from the boundary minutes later, but the Pies answered in commanding fashion with Steele Sidebottom and Dick kicking goals on the run within a minute of each other.
The Magpies led by 38 points with a quarter to go, but the Power didn't appear perturbed by the margin when the first goal went to Jacob Surjan within two minutes.
But, two quick majors to Dick and Didak put the contest beyond the Power eight minutes into the final stanza.
Collingwood will now play Melbourne next Monday in the Queen's Birthday clash at the MCG, while Port Adelaide will return home to host Fremantle on Saturday night.
Collingwood 3.1 6.5 15.8 17.12 (114)
Port Adelaide 5.2 7.5 9.6 11.10 (76)
GOALS
Collingwood: Anthony 4, Didak 3, Dick 3, L. Brown 2, Lockyer, Swan, Davis, Clarke, Sidebottom
Port Adelaide: Ebert 3, Gray, Rodan, Cassisi, Tredrea, M. Westhoff, Lade, Surjan, Pearce
BEST
Collingwood: Swan, L. Brown, Dick, Pendlebury, Anthony, Fraser, O'Brien
Port Adelaide: Cassisi, Boak, Chaplin, Pearce, Salopek, K. Cornes
INJURIES
Collingwood: Nil
Port Adelaide: D. Motlop (ankle) out, replaced in selected side by M. Westhoff, C. Cornes (calf)
Reports: Nil
Umpires: Margetts, McLaren, Armstrong
Official crowd: 34,793 at the MCG
The views in this story are those of the author and not necessarily those of the clubs or the AFL.
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