The Geelong captain unleashed one of the all-time great individual finals games to rally the Cats after a slow start and lead them to a 17.13 (115) to 13.7 (85) preliminary final win over Hawthorn.
But reaching a third grand final in six years has come at a massive cost, with Stewart subbed off in the first term because of concussion.
That means the Cats vice-captain will miss the grand final on Saturday week against either Collingwood or Brisbane.
"He's one of my great friends. It's not just the playing part for me, it's the person he is," Dangerfield said.
"He's been such an enormous part of the success we've been able to have as a club over a long period.
"So it's a really difficult one to digest for us - I'm enormously proud of our guys and the way they were able to cover such an enormous loss that is him.
"But the game was just half-an-hour ago - I'm not too sure what to think."
Dangerfield had Hawthorn coach Sam Mitchell wishing that he would retire after he put the Cats on his back and led them superbly to the win.
They had lost Stewart, fellow defender Jack Henry was nursing a sore ankle and were on the brink at 21 points down when Dangerfield kicked their only goal of the first quarter.
It was the first big moment of his preliminary final masterclass, which featured 32 possessions - 21 of them contested - eight clearances and three goals.
Dangerfield was asked if he was aware just how well he had played.
"As a player, it's about the next moment and what you can control," he said.
"You learn that over time. I don't review forensically always and live in the past of whether it's a good performance or a poor performance.
"You learn from it, you move forward and you don't really spend too much time worrying about people write or say.
"It's more about the coaches and what I can learn. So it's nice to play well, it's nice for us to play well, to execute, and to feel like our game is in a good place."
Dangerfield also spoke of his joy at the Cats being one win away from their second premiership in four years.
"It's enormously rewarding - it can be the greatest week of your life and end in one of the hardest days to digest," he said."
"So it's about enjoying tonight ... we've given ourselves a chance.
"So much of finals is absorbing pressure and then applying your own. They pressured really well and we didn't execute super in that first quarter.
"There was plenty that we needed to address that was not just their pressure, but how we were using the ball. We did that a lot better from quarter time onwards."
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