Kathy O'Hara is brimming with confidence for her Caulfield Cup ride Single Gaze, 18 months after she fell from the mare in their first run over 2400 metres.

Single Gaze will have no trouble completing the Caulfield Cup despite never finishing over 2400 metres, regular jockey Kathy O'Hara insists.

The inseparable pair will jump from barrier 12 in a field of 17 for the $3 million race on Saturday in an attempt to claim the five-year-old mare's first win this spring and her sixth from 27 starts.

It's their second go at 2400m after O'Hara fell from Single Gaze during the Group One Australian Oaks at Randwick in April last year, needing surgery for a complex dislocation near her collarbone, two weeks after they won the Group One Vinery Stud Stakes (2000m) at Rosehill.

Single Gaze is one of only three Cup runners with no history racing over 2400m, or 1-1/2 mile (2414m) for the internationals, with He's Our Rokkii and Abbey Marie also making their distance debut.

"I think she'll be all right with the journey," O'Hara told AAP.

"Her prep has been faultless. She's gotten miles in her legs and everything has gone to plan so far."

The Cup is a seven-day back-up for Single Gaze after she ran fourth in the Caulfield Stakes over 2000m.

But O'Hara echoed trainer Nick Olive's sentiment that the tough mare performs at her best with a tight turnaround.

"I'm not worried about the back-up at all. I think it suits her," O'Hara said.

Single Gaze won the Group Two PJ O'Shea Stakes (2200m) at Doomben in June on a two-week back-up and came second in the Brisbane Cup a week later. She has a 50 per cent record of a win or place from 26 starts.

"She's only got to go another furlong (200m) which I think she'll have no trouble with. She feels like she'll just go all day," O'Hara said.

Saturday will be the seasoned jockey's second Caulfield Cup after she was unplaced on Wild Iris in 2005 when the race was won by Railings.

"It's been a long time, over 10 years. I'm really, really excited and she's a genuine each-way chance," she said.

"Single Gaze is on song and I'm looking forward to it."