"He was totally stoked, they do five races during the weekend. He was winning the first race, but the hometown favourite [Leeston's Kase Thoms] just got him on the last lap. The rest of the day he was sort fighting for second in each race," Susie said.
Overall, Delton finished second in four of the races, and fifth in one where he suffered a "minor hiccup" on the last lap, to finish 11 points clear of third-place finisher Declan Connors, of Taupo.
She said the dry conditions were a challenge for Delton, but he adapted well.
"He went out in practice and he sort of sat back in about fifth and really analysed the track, chose his lines, and come first race he was confident to just go for it. It was quite a technical track because it had a mixture of flat corners, big jumps and sawdust sections - definitely not for the faint-hearted."
Delton and his father Darrel Manson spend time before each race analysing the track together and working out a strategy.
"He adapts instantly, he'll do it and he listens - he loves taking advice from others to improve his riding," Susie said.
Delton started riding when he was 4 and fell in love with the sport, spending every spare moment he can find on two wheels.
"Darrel grew up riding and when the kids were little they loved the little battery powered motorbikes. Darrel still had his first ever motorbike and they started riding that - the passion just grew.
"It's a really cool family sport, every weekend we're off, we go camping with other families and stay at the different tracks."
Final standings from the 2017 New Zealand Mini Motocross Championships
9-11 years 65cc:
1. Tyler Wiremu (Darfield) 125 points
2. Kobe Thoms (Leeston) 100
3. Seth Morrow (Invercargill) 95
7-8 years 65cc:
1. Kase Thoms (Leeston) 125 points
2. Delton Manson (Rotorua) 104
3. Declan Connors (Taupo) 93
7-11 years small trail bike:
1. William Pluck (Cambridge) 122 points
2. Owen Ellis (Motupiko) 113
3. Lachlan Clearwater (Palmerston) 94
7-11 years big trail bike:
1. Alex Gilchrist (Dunedin) 125 points
2. Sam Pickens (Christchurch) 108
3. Ryan Tangaroa (Pukekawa) 128
6-8 years' 50cc:
1. Maz Parkes (Pahiatua) 118
2. Luke Riley (Aria) 92
3. Jack Ellingham (Herne Bay) 87