The three-times world champion was paddling out to ride his first wave in the final of the World Surf League's J-Bay Open on Sunday when an unidentified species of shark knocked him off his board.
Fanning, 34, managed to fight off the circling predator with his fists before returning safely to shore, becoming an overnight international celebrity after video of the incident went viral around the world.
While admitting it would take him a while to process the incident -- "maybe a week, maybe a month," he said -- Fanning was determined to get back on his board.
"Surfing's got me through the hardest times in my life, so to turn my back on surfing wouldn't be right," he told a packed news conference near Sydney airport.
"To walk away from a shark attack with not a scratch on you is a miracle really. You just count your lucky stars and if there is someone up there looking out for me, well thanks."
The camera that captured the incident was unsighted by a wave for the second part of the attack and Fanning tried to fill in the gaps.
"If you look at the footage closely, there's more splashing as the wave goes down and that's when it came back for a second go at my board," he added.
"I felt so insignificant, the thing was so powerful and just moved so fast ... I just ran on instinct and knew that I had to get away from this thing. Once my board was gone, I was just waiting for it come and take a leg or two."
Fanning paid tribute to fellow surfer Julian Wilson, who was competing in the final against Fanning and paddled towards his compatriot when he saw the shark attack.
Wilson has been proposed for a bravery award by the Premier of his home state Queensland for his actions but he said all such accolades should go to Fanning.
"I froze trying to assess the situation and Mick fought and it was probably that that gave me the courage to go towards him," Wilson said.
"I think if any award was going to be given out, they definitely go to Mick for his amazing courage. I don't know how many people would have taken that thing on."
Fanning said he was far from a "superhero" and coming face to face with a shark had been a "humbling" experience.
"We're in their domain and it's like going into a lion's cage," he said.
"If you jump in the cage then one day your number's gonna come up. I guess I'm just lucky that it wasn't my time, it gave me the shock of a lifetime."
Fanning praised the organisers of the event for the speed with which the rescue craft got to him and said he would probably return to Jeffrey's Bay, despite South Africa's waters being among the most shark-infested in the world.
"J-Bay is such a beautiful place, probably among my top three favourite places in the world," he said.
"I've got to go back, it'll be hard but I'll deal with it when it happens."
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