His mind raced as he wondered how he would get out of this one.
"I think both the croc and I had a moment where we were going, 'well, what do we do now?'" Dickmann told 7NEWS.
The Queensland ranger had gone fishing at Captain Billy Landing, a remote area on Cape York.
As he decided to call it a day, he reeled in and turned around.
"The first thing I see is this croc's head just come at me," he said.
"I didn't hear it. I didn't know it was there.
"The thing had come up on the side of the rock platform behind me, out of vision, and was stalking me from behind on dry land."
The snap of its jaws "will haunt me forever", Dickmann said.
"It was quicker than your mind can register," he said.
It bit him on the front of the left thigh. He "tussled" with the 2.8 metre beast and was flung to the ground.
He felt the "bulletproof" reptile try to move him into the water, before Dickmann noticed a vulnerability.
"The only soft spot I found was its eye socket," he said.
He went at it with his thumb. It death-rolled before biting him again on the wrist.
"As it's grabbed me, I'm trying with the eyeballs again," he said.
"I'm getting closer to the edge of the water. It's done another death roll.
"As it's rolled, it's ripped all the flesh off the top of my hand."
He went at the eyeball yet again.
"My thoughts were, 'I'm going to try and push it into its brain'," Dickmann said.
"I pushed it down as far as my thumb would go.
"It let go."
'The first thing I see is this croc's head just come at me.'
He rolled on top of the croc and pinned its jaws.
The croc went for the water, dragging Dickmann "as if I wasn't there".
He picked up its snout as high as he could and flicked the croc down.
It slid into the water.
A "very thankful" Dickmann knows how lucky he is.
The bite narrowly missed the femoral artery in his thigh, and he has full use in his hand despite having the skin ripped off it.
It remains heavily bandaged.
"It could have been a lot, lot worse," he said.
"People keep telling me to buy a lotto ticket but I think I've used all those points up."
This story was first published on 7News and has been re-published here with permission.