Werther defied the might of the Chris Waller stable to storm into Queensland Derby contention when he won the Group Two Eagle Farm Cup at Doomben on Saturday.

Ridden by Jim Byrne, Werther ($4.60) joined Balmerino (1976) and Rising Fear (1986) as three-year-olds to win the Cup in the past 40 years when he scored by 2-1/4 lengths.

"I was rapt to ride him today and looking forward to stitching up the ride in the Derby," Byrne said.

"With the light weight today he was always going to have a turn of foot and I was really happy with the way he switched off during the race."

Trainer Andrew Campbell said Werther would back up in next Saturday's Group One Queensland Derby (2200m) provided he comes through the Cup run without a hitch.

Part-owner Tom Heptinstall was more emphatic.

"Don't worry about whether he eats up or not - he'll be running in the Derby," Heptinstall said.

Heptinstall has enjoyed immense success in the past decade, winning the Victoria Derby with Sangster as well as feature races with Cauthen and Tavistock, the sire of Werther.

Campbell said it was always the plan to bring Werther to Queensland after he ran second to outstanding filly Delicacy in the South Australian Derby on May 9.

"It was a great thrill taking on the older horses and being the first three-year-old to win the race for many years," he said.

"Because of the small field we weren't really sure where he'd settle but Jim summed it up perfectly and rode him a treat."

Moriarty was denied back-to-back wins in the Cup but is likely to back up in next Saturday's Group Two Brisbane Cup (2200m), a race he won two years ago.

Waller said Hawkspur, Foreteller and I'm Imposing would more than likely head to the spelling paddock.