The prolific midfielder limited Brisbane Lions star and fellow Brownlow medallist Lachie Neale's influence in Saturday's season decider and found plenty of the ball himself.
Mitchell finished with 24 disposals, seven clearances and a game-high 13 tackles.
But his place in the Magpies' flag bid was in serious jeopardy when he hurt his back before the penultimate game of their campaign.
"I did it actually in the warm-up before the preliminary final," Mitchell told AAP.
"I was touch-and-go to take the field in the last minute there, just before that game.
"I pulled up a bit ginger the next morning and had an injection straight after that.
"That's part of footy. Everyone's carrying little injuries and you've just got to find a way to push through it."
The 30-year-old, who will break the 200-game barrier early next season, drew on his experience during grand final week.
He always had belief he would be fit to play against the Lions.
"As you get a little older you learn to know what you can and can't play with," Mitchell said.
"This is one of those things I thought I could manage and play with."
Mitchell was one of Collingwood's important off-season recruits, along with Norm Smith Medal winner Bobby Hill and unlucky forward Daniel McStay, who missed the grand final through injury.
And Mitchell ended as one of only four players - along with Josh Daicos, Isaac Quaynor and Jack Crisp - to feature in every game for the Magpies this season.
"I just wanted to come in and play my role and play to my strengths," he said.
"Fly (Craig McRae) and the coaches were so good at backing me in and saying this is what we want from you.
"They had so much confidence in me to do it and I get a lot of belief in myself as well when you've got them in your corner."
Still, Mitchell didn't expect a premiership would automatically happen when he joined the team that rose from 17th in 2021 to a preliminary final in McRae's first season at the helm.
Mitchell was drafted by Sydney in 2013 - a year after their last premiership - and played in the Swans' 2016 losing grand final side before moving to Hawthorn from 2017 to 2022.
"You still pinch yourself," Mitchell said.
"Moments like right now, you never think anything like this could ever happen, so it's pretty special."
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