The Richmond midfielders who bought a stake in a racehorse for a bit of fun didn't win the $1.5 million Victoria Derby grand final, but did get their day out at the races.

Favourite Ace High claimed the Derby for former champion South African trainer David Payne, who moved to Australia in 2002 to start a new life in Sydney.

"It's always been my dream to win one here (in Victoria)," Payne said.

"It's just taken a while but let's hope it continues."

Main Stage, the horse that has become known as Brownlow and Norm Smith medallist Dustin Martin's horse even though the Dusty Boys syndicate only has a five per cent stake, came fifth.

"It ran in the Derby," Tiger Dion Prestia told AAP.

"I don't really care where it finished.

"For it to run today is pretty special."

The midfield group thought buying a stake in a racehorse for fun would lead to a day out at a country race meeting.

Instead, they ended up in the mounting yard at Flemington Racecourse on the day considered by many purists to be the best day on the Australian racing calendar.

Main Stage's large group of owners includes the Dusty Boys of Martin, Prestia, Josh Caddy, Reece Conca, Anthony Miles, Toby Nankervis and assistant coach Andrew McQualter, while Richmond runner Richie Horrocks also has a stake.

It was Horrocks who gave McQualter the tip about Main Stage. He then shared it with the group.

"We were happy to go to the country races," McQualter said.

"We've had a good journey."

McQualter doesn't think the Dusty Boys will be adding to their racehorse ownership any time soon.

"We'll just keep enjoying this ride and see what happens."

The next stage of the ride may end up being an attempt at the $2 million Australian Derby in Sydney in April.

"Main Stage, I think the world of this horse," co-trainer Natalie Young said.

"I think for him doing what he's doing now when looking at him he's definitely an autumn horse, he's going to have a bright future."

His stablemate Sully was the best of Young and partner Trent Busuttin's three Derby runners, finishing second.

Martin opted not to join the 87,526-strong crowd at Flemington on Saturday.

But the world's fastest man Usain Bolt was back at Flemington, after enjoying his Oaks Day experience last year.

Outside the Derby, the day's other Group One races went to the Aaron Purcell-trained Merchant Navy (Coolmore Stud Stakes), Anthony Freedman's Shoals (Myer Classic) and the Chris Waller-trained Shillelagh (Kennedy Mile).