Lion's Roar is set to give O'Shea his first classic success in the Group 1 $2 million ATC Bentley Australian Derby (2400m).

O'Shea has had plenty of success with three-year-olds at feature race level including two Golden Roses with Exosphere (2015) and Astern (2016), Doncaster Mile with Racing To Win (2006), Rosehill Guineas with Zabrasive (2010) and also Lion's Roar in the Randwick Guineas earlier this year.

Despite an outstanding two-decade training career that has netted more than 1500 wins including 29 at Group 1 level, O'Shea is still to win a Derby, coming closest with Zabrasive who ran fourth to Shoot Out and Descarado 11 years ago.

But Lion's Roar is looming as O'Shea's best chance so far after impressive lead-up form including his Randwick Guineas win before a luckless last start fourth in the Rosehill Guineas.

O'Shea said Lion's Roar is peaking at the time for the Derby, pleasing the trainer with a particularly good gallop at Randwick on Tuesday morning.

"Lion's Roar is in a good spot and I think he is a better horse at Randwick,'' O'Shea said.

"He likes to make that long, swooping run and he can sustain a sprint. I feel for a horse with his profile he is better suited being at Randwick.

"We are really happy with the way our horse is going and if he can get a nice run in the race he will go well."

Lion's Roar is on the fourth line of betting for the Derby at $9.50 behind favourite Montefilia at $3.60 with Sky Lab next at $5. New Zealand Derby winner Rocket Spade is at $8.

Sky Lab, Montefilia and Lion's Roar finished in that order immediately behind Mo'unga in the Rosehill Guineas.

With Mo'unga starting in the Doncaster Mile, the Rosehill Guineas is the right form reference going into the ATC Australian Derby, according to Gary Crispe of Racing And Sports.

Crispe said Lion's Roar brings with him the highest Timeform rating of 120 earned winning the Group 1 Randwick Guineas two starts ago, followed by Sky Lab on 118 and Montefilia next best at 114.

"Lion's Roar was held up for a run in the Rosehill Guineas last start but when clear he still found the line very strongly," the form guru said.

"It could also be argued he may have been slightly disadvantaged by where he was in the ground as both Sky Lab and Montefilia made their runs deep on the track.

"A winner of four of his eight starts, Lion's Roar is a very progressive three-year-old and should run a strong 2400m."

Crispe said Montefilia, already a dual Group 1 winner, is a very real chance of joining Shamrocker (2011) as the only fillies to win the Derby this century.

"There was a lot to like about Montefilia's Rosehill Guineas run," Crispe said.

"She was second-up and jumping from 1400m to 2000m and she showed no signs of easing off over the closing stages just going down in a three-way finish. I'm sure she will improve again off that effort.''

The Paul Perry-trained Sky Lab is a promising young stayer storming through his grades this autumn.

"Sky Lab improved his Timeform rating by 20 points in the Guineas to 118," Crispe said.

"If he can build on that run in the Derby, he is going to be right in the finish."

Online article taken from the Mercury.