Blue Diamond aspirations had to be scrapped with Secret Agenda because of injury but the filly has returned in winning style at Sandown.

Secret Agenda was among the leading Blue Diamond contenders this year after a convincing Moonee Valley win on debut but was injured at her next start.

She broke a splint bone and had to have 10cm of it removed.

"It's a non-weight bearing bone," trainer Mick Price explained.

Price opted for a midweek return for Secret Agenda but the trainer is looking to step the three-year-old straight back to Group company after the won The Grand Hotel Frankston Handicap (1200m) on Wednesday by a length.

First starter Spieth turned in an eye-catching debut for second with Braccenby 1-1/4 lengths away third.

Price thought Secret Agenda was "still a bit tubby" and expects her to improve considerably.

"She's a very smart filly and carried herself through in that race," Price said.

"I've got some nice plans for her in stakes races coming."

Price will keep Secret Agenda to sprints and the Group Three Champagne Stakes (1200m) at Moonee Valley this month is an option for her next start.

Multiple Group-placed mare Lucky Lago made a winning start for new trainers Lee and Anthony Freedman in The Cove Hotel Handicap (1200m).

Lucky Lago races in the colours of owner Keith Biggs, silks made famous by Freedman's Melbourne Cup winner Doriemus.

Freedman said Lucky Lago, formerly trained by Peter and Paul Snowden, was transferred to him by the owners for a Melbourne campaign and was hopeful the mare could snare a Group win.

"I'm grateful to the Snowdens who sent her down in magnificent condition which made my job very easy," Freedman said.

"She'll be aimed at mares' set-weights and penalty races and we'll just see how far she goes. The Myer Classic might be a bit strong, but we don't know.

"There's improvement in her off today."

Lucky Lago ($5.50) stalked the favourite Japhils ($2) before fending her off in the straight to defeat Judicial Rock by a length.