Next came Fraser Babbington (Gisborne), on HCPH Blinky Bill, who wasted no time in bettering Causer with a 34.75 clear effort.
Tombleson and Mr Shelby jumped third and were deceptively fast - a slick inside turn giving them the much-needed edge to come home clear in 34.19.
Last to go was Vicki Wilson (Hawke’s Bay), on her showy homebred Dark N Spicy, who had the fastest time of the round - 33.07- but dropped a rail mid-course.
“I had to work for it out there to beat Fraser (Babbington),” Tombleson said.
The win was even more special as Mr Shelby is out of Fraser’s World Cup mare Mea II, who won the Six-Year-Old crown at HOY a few years back, but died in a paddock accident.
“It’s pretty cool he’s out of Mea,” said Tombleson, who farms 1000 hectares on the outskirts of Gisborne. “I think he’s definitely showing all the right signs, but I am just not sure I am the one to do it with him.
“Any title class is neat to win and with just one horse here, I try to make it count.”
The Horse of the Year is New Zealand’s premier equestrian event, featuring 1400 riders from all over the country.