Allan said he was happy with his paddle on Blue Lake that left him only one minute behind the leader, Ussher, setting him up for the rest of the course.
After picking up some time on the 30km mountainbike ride he was able to chase down Ussher in the run.
Allan was met by a big group of supporters when he crossed the finish line next to the Redwoods Visitor Centre, including his fiancee Amy Nunn from Wanaka and parents from Foxton.
Allan's next big event will be his wedding later this year.
Ussher said he was happy with his race and Allan deserved the win.
"I'm delighted by the result today and I was beaten by the better man," he said.
"It was a fantastic race on a great course. The bike [section] is quite technical and you are always trying to find the medium between speed and keeping control," he said with a laugh.
Ussher did not have to wait long after finishing the race to congratulate his wife, Elina Ussher, who finished third in the premier women's race.
Rotorua's Nic Leary was the pick of the local athletes in yesterday's premier race, finishing fifth in the women's event six minutes behind Wanaka's Simone Maier.
Maier was all smiles when she crossed the line to a round of applause, winning the women's race in a time of 3h 04m 04s.
"It's amazing," she said. "It is amazing because there was such a strong field out there today."
Maier, who works as a lifeguard alongside event winner Allan, resisted competition from the best women's field seen at the event including Speight's Coast to Coast defending champion Sophie Hart, who finished second.
