The 10yr-old squaregaiter simply bolted in in last night's feature trot with a bold frontrunning display for driver Nathan Williamson.
The trotter's third win of the season gives his trainer a career-best season at 84 years old.
Exactly why Holdon Toyaspurs has shown the form that has led to that is a mystery to Prendergast.
"I don't know why he is going so good; I have no idea," he said. "He is doing exactly the same as he did last year and then he was going no good at all."
Holdon Toyaspurs made Prendergast the oldest driver to win a race in New Zealand when they won at Forbury Park in 2014.
Prendergast is also in the running for the title of oldest trainer of a winner, but giving him the title is a little tricky, as the official record has not been made public.
Prendergast shares Holdon Toyaspurs' ownership with his daughter, Tania, and neighbour Simon Russell.
The horse has given Russell the ultimate introduction to horse racing.
Holdon Toyaspurs is the first horse he has raced and has been so consistent during his eight seasons of racing Russell has funded his training fees through his winnings, Prendergast said.
Williamson scored a driving double last night when he won race 9 with Scarlett Lane, a horse he trains.
The victory was Williamson's 200th win as a trainer.
