The emotion surrounding Williams’ shock exit earlier in the day was evident in the first quarter, with the inspired Power holding the Pies goalless on their way to a 32-point quarter-time lead.
The visitors steadied to level the scores at half time and took a narrow one-point lead into the final change, but Port Adelaide couldn’t maintain its intensity in the final term and Collingwood piled on four of the first five goals to secure the hard-earned win, 16.9 (105) to 12.7 (79).
Ball magnet Dane Swan (39 possessions, seven clearances and a goal), acting captain Scott Pendlebury (30 possessions and five tackles) and forward Alan Didak (20 possessions and two goals) were instrumental, while Chris Dawes proved handy in attack with three goals.
David Rodan (26 disposals and three goals), Steven Salopek (22 disposals), and Dean Brogan (15 touches and 25 hit-outs) tried hard for the Power, while Brett Ebert started brightly with four first-half goals.
There were queries over how the Port Adelaide players would respond to the events of the day and they made their intentions clear from the opening bounce.
With the aid of a strong breeze, the Power had two goals on the board before the Pies could get the ball over halfway and consecutive majors to Ebert saw the home side extend the lead to 26 points.
Travis Cloke vented his frustration and was subsequently reported for striking Travis Boak behind play as the Power continued to dominate.
Collingwood steadied towards the end of the term, but managed just a solitary point into the breeze before Rodan’s first goal increased the margin to 32 points at the first change.
The Power skipped further ahead in the second term, after goals to Ebert and young midfielder Mitch Banner but the quarter belonged to the Pies.
Swan ignited the visitors, picking up 16 possessions, six inside 50s and a goal for the term and Didak escaped Kane Cornes’ tag to kick two important majors as the Pies levelled the scores at half time.
Rodan and Josh Carr did their best to lift the Power in the third term but Collingwood kicked three goals into the breeze to lead by a point at the final change.
The Power were down to 21 fit men, after losing midfielder Matt Thomas to a corked thigh and Collingwood capitalised with three goals in the first eight minutes to secure the victory.
Williams addressed the players briefly after the game, but declined to hold his standard post-match press conference and made a swift exit from the ground with his family.
Power football manager Peter Rohde fronted the media in his place and said it had been a tough day for all involved and in particular the departing coach.
"It’s a very tough industry and I think that everyone around our club has understood today more than ever before how it’s a performance industry,” Rohde said.
“I think Mark did himself very proud this afternoon. He left with some very good messages about watching their careers and certainly left the place not bitter and twisted.
"It’s a tough gig and there are a few of us that have been through it. He handled it as well as anyone as well as I’ve ever seen."
The Pies had a fight on their hands for the first three quarters until the Power faded and coach Mick Malthouse said it was hard to prepare his players for a game against an emotionally-charged opposition.
“How do you plan for something that you don’t know how it’s going to pan out? All of a sudden, you’ve got your backs up against the wall and you have to fight tooth and nail to win the game,” Malthouse said.
“All the aspects of it were falling into place for Port and all the things that we pride ourselves on were going out the window.”
The win puts Collingwood on top of the ladder temporarily, while the Power could slip to as low as 15th.
Port Adelaide is expected to make an announcement on its interim coach on Monday.
Port Adelaide 5.3 7.5 10.7 12.7 (79)
Collingwood 0.1 7.5 10.8 16.9 (105)
GOALS
Port Adelaide: Ebert 4, Rodan 3, Motlop 2, Banner, Carr, Stewart
Collingwood: Dawes 3, Didak 2, Blair 2, Brown 2, Thomas 2, Beams, Cloke, Jolly, Lockyer, Swan
BEST
Port Adelaide: Rodan, Salopek, Brogan, Ebert, K. Cornes
Collingwood: Swan, Didak, Pendlebury, Beams, Shaw, Thomas, Jolly
INJURIES
Port Adelaide: Thomas (corked thigh)
Collingwood: Nil
Reports: Travis Cloke (Coll) for striking Travis Boak (Port)
Umpires: Donlon, McBurney, Avon
Official crowd: 24,260 at AAMI Stadium
The views in this story are those of the author and not necessarily those of the clubs or the AFL.