An impressive debut win at Sandown to two-year-old Devil's Harmony might have surprised some people associated with the filly, but not jockey Michael Walker.

Devil's Harmony stepped out in the Taralye Plate (1200m) and sprinted quickly in the straight after settling midfield to win by 2-1/4 lengths.

Walker said he formed a good opinion of the filly after a trackwork gallop at trainer David Hayes' Euroa property last week, but stable representative Bruno Rouge-Serret said the winning performance was unexpected.

"We weren't expecting her to just win like that," Rouge-Serret said.

"We thought she would run a nice race but thought she would be back and see if she could run home over the top of them.

"But she was closer in the run and ran over the top of them quite easily."

Rouge-Serret said Hayes would consider what to do with the filly once he sees how she comes through her debut.

"There's no set plan. We might have to re-arrange a few things now but we'll leave that to Dave," he said.

Walker said he gave Hayes a good report on the filly after riding her in a gallop last week.

"I said she would be very hard to beat. She's got a lot of upside to her," Walker said.

Devil's Harmony ($13) defeated Notonyourlife ($6) with Choix de Maia ($16) third.

A double to Harry Coffey moved him equal with the injured Patrick Moloney at the top of the Melbourne city apprentices' standings for the season with 23 wins.

Coffey scored aboard the Mick Kent-trained McNulty and the Anthony Freedman-trained Stradale but said he wasn't getting carried away with premiership ambitions just yet.

Coffey also leads the statewide apprentices' title.

"There's a fair way to go so I'll just keep chipping away," Coffey said.

"I might focus a bit on it if I can hold my lead, but I've got very good apprentices chasing me."