For a horse as fragile as Choise Achiever that should have been the only excuse he needs to get beaten but he surprised Butt by showing great courage to claw back past the favourite. It was the culmination of some perfect planning from the Butts as they have long realised that Choise Achiever is a little physically slight for the rigours of the Grand Circuit and that the Hunter was his chance of a lifetime.
Their plan - use manners and a sharp sprint - was executed perfectly.
But the rest of the day was Purdon's as he had 90 minutes earlier downed the Butts' trotter Vulcan in the Interdominion Final.
And six hours earlier, even when the Butts thought they had won the $200,000 Sales Series Pace at Addington with Elusive Chick, they had not.
The three-year-old filly led throughout to win the richest race of her career but then lost it in the inquiry room because of running up the track in the home straight and inconveniencing Dancing Diamonds, trained by Purdon.
"I didn't even know she had lost the race in the [inquiry] room because I was listening in the car and turned it off happy after she had won," said Anthony Butt.
"So I am disappointed about that one but we came here to win the Hunter and we have done that.
"And it is that much more satisfying when you beat trainers like Mark.
"We are good mates with him but it is also a good rivalry and we love beating him because you are beating the best.
"But today, well [it] took the whole thing to a new level."
The day provided some staggering statistics, with Anthony's six winning Hunter Cup drives complemented by Tim's four training successes in the race and Purdon's five Interdominion Trotting titles.
While the machine of racing presses on relentlessly - next stop the pacing Interdoms in Perth - days like Saturday remind you how lucky harness racing fans are to have so many future Hall of Famers in their midst at the moment.
Choise Achiever won't be going to Perth, instead returning to Auckland possibly for the Auckland Cup, with the Butts having Raglan flying their flag in Perth.
And there to take him on will be Purdon with Auckland Reactor, who was so brave after settling 40m from the leaders off his Hunter handicap.
"I think he won a lot of fans over in Australia tonight because he was an awfully long way off them early," said Purdon.
Surprisingly Auckland Reactor returned to New Zealand last night and will rest here before flying to Perth next week.
While the Kiwis dominated Saturday night's group ones at Melton, South Auckland pacer Ideal Scott found his second line draw too much to overcome in the A$200,000 Victoria Derby but was a run-of-the-race runner-up to leader Scandalman.
And at Addington, Carabella used her better draw to down arch-rival Bettor Cover Lover again in the $100,000 Breeders Stakes, while Sir Lincoln and Dr Hook were other stars on one of Australasian harness racing's biggest days of the year.