One of 20 fighters in his age group at the championships which attracted 1500 competitors from 15 countries, Kupa was disqualified in his points section.
"I was disqualified at my three previous world championships so I had to smile to myself when I got the latest one," he said.
Kupa and one of his proteges, the Hikoi for Life-sponsored Anahera McClutchie, were the only Hawke's Bay fighters among the Kiwi contingent at the invite-only championships.
McClutchie, 20, won bronze for placing third overall in her 22-strong open women's black belt division and also recorded a second placing in weaponry and a third in kata.
A third year sport and recreation student at EIT, McClutchie, has been a karate exponent for 10 years.
"I was happy with bronze as it was such a hard competition. I finished 17th at my last worlds," she explained.
Although she is a more than handy netballer and waka ama paddler, McClutchie ranks karate as her main sport.
"I want to give back to the young ones. I've got a lot of cousins and nieces involved and I want to help them follow my path.
"Whanau involvement was a big key to my success in Sydney as so many of my relations have helped me over the years. The day before we flew out I attended my aunty's tangi at Waimarama and my bronze was dedicated to her," McClutchie said referring to her late aunty Yvonne Te Whaiti.
She will get another crack at the Aussies at a transtasman event in Rotorua next weekend.