Some advice from one of the country's best jockeys has helped Blake Shinn guide Victorian stayer Mr O'Ceirin to a dogged Grafton Cup victory.

Shinn, who was riding the horse for the first time, revealed a conversation with the five-year-old's regular jockey Glen Boss provided a critical insight as Mr O'Ceirin staved off all challengers to win the 100th running of the NSW country feature on Thursday.

"Bossy rang me last night to tell me about this horse," Shinn said.

"The key to him is to get him in a really good rhythm. He doesn't have a sprint.

"The two leaders set it up for me early to work across into a position.

"Once I got that position he was always in cruising mode."

Mr O'Ceirin was an impressive winner at Moonee Valley two starts ago before failing as an odds-on favourite at the same track on June 29 when he was found to have choked down.

The gelding bounced back to his best in Thursday's 2350-metre Listed race, camping on the back of the leaders and outstaying the chasers to score.

Maher praised the navigation of Shinn who kept a cool head despite drawing the outside alley in the 16-horse field.

He also revealed he had second thoughts about running Mr O'Ceirin when he learned of the gelding's tough draw.

"He drew the car park and it was quite a decision to make the trip up but I was already in Sydney when the draw came out," Maher said.

"It was a great ride by Blake - he was pretty cool - there was a bit of pressure early."

Maher said Mr O'Ceirin would return to Warrnambool for some beach work before being aimed towards the Moonee Valley Cup.

Mr O'Ceirin's win ensured he has passed a ballot clause for the Melbourne Cup.

The Grafton Cup-Melbourne Cup double was completed by Kensei in 1987.

Mr O'Ceirin firmed from $7 into $5 and had a half-neck to spare over Yulalona ($31) with Reuben Percival ($6.50) another neck away third.

Favourite Destiny's Kiss ($4.40) was jagged back to last from his wide draw and did his best work late to finish fifth.