Nairn is based in Canterbury and because of stable commitments at home decided to leave Lotalov in Auckland to prepare for today's glamour meeting.
He had no hesitation leaving her with young MacKinnon, who starts work at Alexandra Park Raceway at 5am most days before joining his mates at school.
"Jack has been helping me out when I come north for a few years and he is a smart young guy and very conscientious," says Nairn.
"So while I have been flying up for her racedays for the last month, Jack has been doing almost all her training and doing it well.
"He has basically been her trainer."
MacKinnon has been interested in harness racing his entire life and first sat in the sulky aged 10.
The long hours with little financial upside don't bother him because he finds being Nairn's northern caretaker trainer has been invaluable experience.
"I want to be a racenight driver soon and then train horses so this is hopefully going to be my career," says the quietly spoken youngster.
"And I'm lucky because my mother, Gayleen, and my brother Oliver [15] help out too."
The early-morning alarm clock isn't the only downside to being possibly the only horse trainer living in Ponsonby.
"It sometimes gets a bit stressful because I get even more nervous than the owners on raceday.
"And this week will be worse because the Jewels are a big deal."
Most of MacKinnon's schoolmates know about his "career" but are oblivious to the success he has helped to achieve. But they might realise next week, as he is likely to skip school to accompany Lotalov across the Tasman to compete in the rich Victoria Oaks.
Still, it's kind of hard to bring his shining achievement, a 500kg horse, to school for career day.
Today's Jewels meeting is one of the biggest harness-racing days in the world, bringing together 106 of New Zealand's best and two Australian stars.
The racing for the rare daytime meeting starts at noon.
