That someone was Farrell, who also recorded the best finish of his young career, while Great Britain representative Haynes closed out the Mount clean-sweep, after winning the previous two eliminator rounds leading into the final.
Omanu 16-year-old Ben Cochrane was fourth, while another Mount athlete, 18-year-old Hamish Treanor, finished a valiant fifth.
The women's final was taken out, as expected, by Papamoa's Natalie Peat, although not in the manner most spectators anticipated. Peat led early in the swim but the chasing pack caught a wave and hauled her in. Mount Maunganui's Katie Wilson opened up a big lead on the ski leg but then lost her ski coming in on a big set wave.
Mairangi Bay's Danielle McKenzie then took the initiative in the final board leg but ran out of waves on the way home. Peat and Piha's Kirsty Wannan chased her down, with Peat's slick dismount on the beach giving her the edge in a sprint finish.
"I'm not really renowned for my sprint finishes so it was good to pull that one out of the bag," Peat, 18, said. "I was leading in the swim and the whole pack came through so I was stoked to get the wave on the board and get back up to the front pack."
The final was the culmination of the four-round Sonic series, which incorporated four of the biggest regional carnivals around the country. More than 800 junior athletes packed the stands during the final, which was held during the Oceans 13 New Zealand under-14 championships.