A Queensland battler versus some of the biggest trainers in Australian racing.

That's what confronts Brisbane hobby trainer Craig Cousins in his bid to claim the $2 million Five Diamonds with The Inflictor at Rosehill on Saturday.

Cousins, who drives a truck for a living, is currently a one-horse trainer and is pinching himself once again that his stable star is a live chance in a race which could finally end his truck driving days.

"I've been driving trucks for a living for around 12 years and if he wins, I'll throw in the truck driving," Cousins said.

"And if he runs in the top three, I'll be the happiest man in the world."

The Inflictor shapes up as a strong hope in the Five Diamonds despite stepping out in distance to 1800 metres for the first time.

The five-year-old has never raced beyond 1600 metres and has only started once at Rosehill when 11th to the Joe Pride-trained Headley Grange in the Alan Brown Stakes over 1400 metres in his first trip away on October 18.

Cousins gave the green light to run in the Five Diamonds after The Inflictor's latest performance when he valiantly tried to lead all the way in the Listed Five Diamonds Prelude over 1500 metres at Randwick two weeks later.

The five-year-old put in a brave effort to go under just over two lengths.

"It's his first go over 1800 metres but there's a few in the same boat," Cousins said.

"He's got to be ridden the right way to get the trip so I'd like to see him with cover and not lead.

"If he gets a sit and some cheap sectionals he'll go well."

Cousins rated The Inflictor unlucky when beaten nearly five lengths in the Group 1 Stradbroke Handicap at Eagle Farm in June.

"It was an enormous run in the Stradbroke and he's still trying to get out," he said.

"We were the bunny for Transatlantic in the Prelude and he's proven he's a fair horse.

'Unfortunately, we meet Transatlantic on the same terms under the set weight conditions."

The Inflictor - an Alysha Collett mount - is a home bred and is owned in a syndicate managed by Kurt Turner, the eldest son of the late trainer and breeder Ken "Tubby" Turner.

Tubby Turner was a larrikin in his era and trained many top horses including Lion Hunter, Just Awesome and Chinchilla Rose.

Cousins will call time on The Inflictor's Sydney campaign after the Five Diamonds.

"He'll go for a break after Saturday and he won't race over the summer when he gets home," he said.

"But I'll be looking to go back to Sydney for the autumn before he has another crack at the Stradbroke."