Trainer Danny O'Brien may be down on numbers, but he has produced a promising two-year-old to win at Caulfield.

O'Brien has found it difficult to attract new business to his stable as he fights a four-year cobalt disqualification before the Victorian Cival Administrative Tribunal.

West Australian owners Barry and Jan McRostie have stuck by O'Brien and were rewarded when Merriest won the Cove Hotel Handicap on Saturday.

Ridden by James Winks, Merriest was backed from $6.50 to $5.50 before scoring by 2-1/4 lengths from Phoenix Rising ($8) with the $4.60 favourite Vintage Quartz a half-length away third.

"Barry and Jan have been very loyal and wanted us to have her," O'Brien said.

"It's been difficult. You can't attract new clients as this situation just goes on and on and on.

"As I say, there's always a lot of people going through a lot worse."

Merriest was a $210,000 Magic Millions yearling purchase and O'Brien said the filly had been through several preparations before making her debut.

O'Brien was confident the daughter of Denman would be hard to beat after winning a Werribee barrier trial earlier in the month.

He has picked out a Flemington 1100m race on May 7 for the filly's next start.

"I wouldn't mind giving her a look at the straight before giving her a break," he said.

"She's going to be a cracking three-year-old."