"I had the perfect weather forecast. I just had to go out there and catch the fish," the 25-year-old said.
Three days into his trip, the West Aucklander was down on his luck after his only would-be catch got away.
For hours he wrestled with the marlin, managing to get it within 10 metres of his craft before the line snapped.
Devastated, Potter, who was in a "bad shape", decided to call it quits because he was mentally and physically drained.
But after a sleep, he couldn't help himself and went back out.
After catching a live bait, he started paddling out to the blue water. Moments later he heard his line click and knew something was up.
Potter's line then started screaming. He turned around and spotted something which he had never seen before.
"This marlin came flying out of the water, and it was jumping straight towards the kayak at full speed."
Although this was Greg Potter's first marlin, he's been an avid fisherman since childhood. Photo / GP Fishing Adventures "I was just blown away," Potter told the Herald.
"I'm hanging on for dear life to this rod and this fish is just giving me a ride and the kayak was just flying in the water."
Potter's main task was to get the leader on the reel so he was able to say he caught the marlin.
At a second attempt, Potter did so.
"I was screaming ... I was stoked," Potter said.
However that was not the end of it. After a few hours in the game of tug of war with the fish, he was towed 15km offshore.
The lengthy wrestle left him physically and mentally drained, as well as suffering cut and blistered hands, and losing feeling in his forefingers.
"I was just elated that all those feelings of pain went away.
Once Greg Potter got the leader on the reel, he pulled the marlin next to the kayak where Elwood Higgins gaffed it. Photo / GP Fishing Adventures "There were a lot of emotions ruining through my mind during that fight."
The gruelling catch saw Potter needing a helping hand, with nearby local boatie Elwood Higgins gaffing the fish.
"Seeing that marlin come up next to the kayak was just incredible," he said.
After a few photos with his catch, Potter made his way to the local game fishing club.
Officially, the striped marlin weighed 94.2kg.
To Potter's surprise he was greeted by locals, boaties and other game fishermen who he had met on his four-day trip.
"It was so special to me that those people were so interested in it."
Because buying a boat was out of Greg Potter's price range he brought a kayak and started kayak fishing. Photo / GP Fishing Adventures Coming to terms with the day he had just gone through, Potter managed to get an hour of sleep before heading back to Auckland.
Over his four-day fishing trip, he spent 27 hours on the water.
A week and a half later, and Potter says he is only just coming to terms with his achievement.