"When I first met Jann at the academy he was very quiet and didn't say boo to a goose," said Herbert.
"He wasn't the best at the beginning and he'd done absolutely nothing in racing. He'd always loved motor racing and when he got to the academy it was like a dream come true for him and he was actually going to get a chance to drive a real race car."
He came out of his shell and started really concentrating on everything after a teammate got a bit cocky and let the side down losing to another pair.
"After Jann's teammate lost a challenge for them he really became more focused, got faster and you certainly knew he was around from then onwards.
"From that point on, everything just took off and despite never being in a race car before [all the others had] he was better than everyone else and won.
"You're probably seeing some of the focus out there in New Zealand in the TRS series now, and how he applies the talent he has and how he can adapt quickly to any given circumstance," said Herbert.
Mardenborough is the leading rookie with one round to go in the TRS and has shown he is capable of scintillating speed in a car he's never seen let alone driven before, and on circuits that are completely new to him.
He's had eight top 10 finishes from 12 races and qualified on the front row for the last round at Hampton Downs.
This weekend's feature race at Manfeild is for the New Zealand Grand Prix and on recent form, Mardenborough is in with a better than even chance of getting his name on that illustrious trophy.
The leading three for the title are defending TRS and New Zealand Grand Prix champion Nick Cassidy who leads the championship from Austrian Lucas Auer and Brit Alex Cassidy.
TRS points after four rounds
1 Nick Cassidy 706
2 Lucas Auer 674
3 Alex Lynn 623
Also:
10 Jann Mardenborough 404