Nick Olive feared the worst when pint-sized filly Single Gaze and her jockey Kathy O'Hara crashed to the turf on the home turn in the 2016 Australian Oaks.

"It was such an horrific fall," Olive said.

"Running up the track there at Randwick, it was pretty tough emotionally."

O'Hara suffered a collapsed lung and dislocated clavicle which sidelined her for two months.

She considered herself lucky.

Single Gaze also needed time to get over the fall and there were times Canberra trainer Olive wondered whether she would make it back to the track.

He brought her back into work twice but wasn't completely happy with the mare either time so waited before taking her back to the races 45 weeks after the fall.

"She was in and out and I had in the back of my mind 'will we get her back. Will she be right again?'" Olive said.

"A bit of patience and we got there."

The fall came only a week after the high of Single Gaze's victory in the Group One Vinery Stud Stakes at Rosehill, Olive's first elite-level win.

Single Gaze has not looked back since returning earlier this year and on Tuesday lines up in the country's most famous race, the $6 million Melbourne Cup at Flemington.

At her most recent start the mare turned in a mighty effort for second in the Caulfield Cup as a $31 chance.

Despite that performance, Single Gaze is at $41 for the Cup but is the worst result for the TAB with many faithful taking the price.

Olive is convinced the mare is again being underestimated.

"I suppose the risk with this race is running over the 3200 metres for the first time," Olive says.

"I feel she's got the qualities to do it, but you never know until you try.

"It's such a gruelling race and she's such a tough horse. I think she's definitely been underrated.

"I do feel she'll run a big race, definitely."

O'Hara rides in her first Melbourne Cup on Tuesday, with Olive saddling his first Cup runner.

"I think it will be a great experience. A great day," Olive said.

"A lot of friends and family and supporters from Canberra are coming down, so there will be a big group down here.

"I've just got to make sure I get enough sleep leading into it so I can enjoy it."