"We had a good battle the whole way between the four of us. Anyone could have won it coming off the last buoy," he added of the battle that took place between him, the two Australians and American Jack Bark.
"I just had to dig in and believe in myself, believe in my training programme and believe in my coach."
Shergold described the course as one of the better ones he has raced with paddlers having to paddle in open ocean and between islands.
"It wasn't a straight paddle, you had to understand the water, the currents and the wind, it was a proper waterman course."
Shergold was joined in the race by the youngest team member, 16-year-old Declan Dempster from Mount Maunganui. Dempster finished his first international race in fifth position, the first paddler behind the much more favoured leading four.
On Wednesday, Armstrong claimed a world title in the SUP women's technical race.
Armstrong was accompanied on the podium by medal-winning performances in the men's and women's technical prone races earlier in the day.
"There was a whole lot of good luck out there today. I am fit but not race ready so there was some luck involved with my wind," she said, who has battled bad health all year and was a late replacement, coming in to the team only two weeks before the event.
Mount Maunganui's Scott Cowdrey capped off a brilliant day on the water with a bronze medal in the men's prone technical race.
Cowdrey battled hard with the Australian one-two combination of Matt Poole and Lachie Lansdown, particularly Lansdown, the two paddling side-by-side for the majority of the race.
On Friday the 17.5km distance races take place for the Women's SUP and Prone Disciplines.
The race will start at Cloudbreak before weaving between the islands of Tavarua and Namotu and finishing at Musket Cove on the island of Mololo Lailai with the top races taking just over two hours to complete the course.
