Persan, who began his campaign with a third in a Wangaratta maiden in April, has claimed a spot in the 2020 Melbourne Cup after winning The Bart Cummings.
His co-trainer David Eustace said three months ago he wouldn't have believed Persan could be in Australia's most famous race.
But three weeks ago, he began to consider it a possibility and he was proven correct after the horse's win in Saturday's 2510 metres Flemington feature.
"He's been an amazing horse to do what he has done. I told the boss (Ciaron Maher) a month ago I felt he had the form to win a race of this nature," Eustace said.
Persan joined the Eustace and Maher stable earlier this year and has won six of his ten starts and finished second on three occasions and third once.
The stable now has three starters in the Melbourne Cup as they already have Etah James and imported galloper Sir Dragonet in the race.
"It's been a great job from everyone in the stable to get him to this point. He's always been a really nice horse," Eustace said.
"He came to us a nervous horse and we had to build his confidence up and build up his condition, which we did at our Ballarat stables."
Eustace said Persan was able to show his staying prowess in The Bart Cummings due to the race being run at a fast tempo.
"The whole way through we said that we just wanted to get him in a race with a decent tempo. We thought we'd see a better horse for that and he'd finally got that today," he said.
Eustace said he was worried that the track was too firm for Persan but he was happy to have been proven wrong.
Persan was ridden by Jye McNeil but he already has a Melbourne Cup ride in Twilight Payment.
Eustace said Michael Dee had put his hand up for the ride.
Persan ($10) defeated Sound ($15) by a length with Steel Prince ($7.50) a nose away third.