Jack, competing in his third and final Colgate Games in Taranaki last weekend, was second in the grade-14 boys 200 metres and third in the 100m.
His father said he showed potential despite feeling under the weather, and there was little between the best athletes.
“Both races were outstanding to watch, with hundredths of seconds separating the first three to four places,” Paul Sadler said.
Jack clocked 12 seconds flat in the 100 final, 0.17secs behind the winner and just 0.03 off silver.
He won his heat and semifinal of the 200 and ran 23.64 in the final — 0.26 behind the winner.
Jack was one of four young athletes from Gisborne Athletic Club to attend the 2020 North Island Colgate Games in Inglewood, Taranaki, and Sadler said it was a great opportunity and experience for them.
The other three were Jack's younger sister Ruby, 11, Kaedyn O'Donnell-Hawkins, 10, and Evelyn Busher, 13.
“Kaedyn O'Donnell-Hawkins had a very good first Colgate Games,” Sadler senior said.
Competing in such a large event for the first time could be daunting but she wasn't overawed.
Kaedyn made the semifinals of the grade 10 boys 100m and 200m. He finished 16th in the 100m, 19th in the 200m, 12th in long jump and 15th in high jump.
Ruby Sadler competed in her second Colgate Games and made the semifinals of the grade 11 girls 100m and 200m.
“A highlight of the competition was Ruby convincingly winning her 100m heat,” Sadler said.
She finished 14th in the 100m and 21st in the 200m.
“Evelyn Busher showed great character throughout the competition,” Sadler said.
“The grade 13 girls is a tough division, with many of the athletes involved in extensive coaching and training programmes.
“Evelyn gave her best in all her races and definitely left everything on the track.”
She finished 22nd in the 100m, 17th in the 400m and 14th in the 800m.
“Gisborne Athletic Club athletes were grateful for the support of parents and whanau and also the support offered by members of the Wairoa, Napier and Hastings clubs.”