Warrnambool boy Ciaron Maher has secured his third Grand Annual Steeplechase with Regina Coeli outstaying her rivals in Australia's longest race.

Negotiating a 5500m journey and 33 fences on testing ground, Regina Coeli joined her half-brother Al Garhood on the Grand Annual honour roll.

Al Garhood gave Maher his previous victories in the race in 2010-11.

Ridden by Irish jockey John Allen, Regina Coeli ($4.80) scored by four lengths from favourite Lord Of The Song with Dhaafer ($11) three quarters of a length away third.

All nine starters completed the gruelling contest including last year's winner Chaparro who finished eighth and almost 70 lengths from the winner.

Maher has won Group One flat races but says Grand Annual success gives him the most satisfaction.

"This is the best race," Maher said.

"I was only telling the trainers at Caulfield the other day to have a runner in it is something else."

Regina Coeli, who became the first mare to win the Grand Annual since Venite in 1983, was backing up after finishing fourth in the Brierly Steeplechase on Tuesday.

Maher believes she is a better stayer than Al Garhood and hopes to set her for the Grand National at Ballarat in July.

"When the rain came I thought it enhanced her chances as she's an exceptional wet-tracker," Maher said.

"I thought the run on Tuesday would back her off a little and she raced perfectly.

"She's only lightly-raced for a jumper at this sort of level."

Allen rode Regina Coeli in her two Warrnambool carnival runs and admitted he was concerned he might have done too much on the mare in Tuesday's lead-up race.

He credited Maher with having the horse in top condition on Thursday.

"Ciaron turns his horses out so well time and time again," Allen said.

"I was in a good spot the whole way and she relaxed throughout the race.

"I gave her a little squeeze over the second last and she gave a kick and I knew then it would take a good one to get past me."