Garth, who was competing in the 11-13yrs trail bike section of the competition on his Kawasaki KLX140L, won the Southland title along with the South Island title.
He said he was totally ‘‘blown away'' by the victory, especially after the problems he had experienced in the first two of the three races.
"In the first two races I had big problems with the kill switch on my motorbike.
"It was positioned too close to the throttle and in the first two races I accidentally hit it, causing the engine to die, which was terrible,'' Garth said.
Despite the hiccups in the first two races, he managed to achieve third place in both, leaving him behind his competition going into the last race.
"Between the second and third races we changed the position of the kill switch, so the problem wouldn't happen again.''
Garth then went out and won the final race to clinch the Southland and South Island Championships in his section by just one point.
"I was totally surprised to have won.''
Garth, a year 8 pupil at Blue Mountain College, found most of his competition in the 11-13yrs trail bike section came from his classmates, with fellow Blue Mountain College pupil Jordan Brand finishing second overall.
Others from the region to compete well in the 11-13yrs trail bike section were Bradley Catto, also of Blue Mountain College, and Brayden Wyatt, of Gore High School.
Although he started riding motorbikes at age four, Garth said he only resumed competing in motocross last year and now had a renewed interest in the sport.
"I try to model my riding style on Chad Reed [Australian-born American motocross and supercross star].''
He said he was aiming to get a bigger bike - a 250cc machine - towards the end of next year and progress to that class of racing.
This year's event was originally scheduled to be run just outside of Garth's hometown of Tapanui, but because the course was too wet, it was transferred to Sandy Point in Invercargill.
"It was a bit tougher not knowing the course, but we got there in the end,'' Garth said.
Lockie Lott (16), of St Peter's College in Gore, competed in the 12-16yrs 125cc class and the 14-16yrs 250cc class.
Lockie finished second in the South Island Championship for both the 125cc and 250cc classes, as well as winning the Southland Championship in both classes.
