Quality filly Shoals has continued an unbeaten start to her career in her first appearance as a three-year-old in the Listed Atlantic Jewel Stakes.

Shoals registered three wins as a juvenile, including two Group race victories, and signalled she can go on with the job as a spring three-year-old with her first-up win over 1200m at Moonee Valley on Saturday.

Giving almost all the other fillies weight, Shoals began brilliantly under jockey Mark Zahra who then elected to take advantage and settle outside leader Blondie, rather than the intial plan to ride her quieter.

Shoals ($4.80) took over passing the 100m to defeat Blondie ($16) by three-quarters of a length with another half neck to She's So High ($8.50) third.

Zahra is convinced Shoals has even more in her, saying she still didn't put the race away like he believes she can.

"I had the horse on her inside (Blondie) covered and thought I had three lengths on her," Zahra said.

"But as soon as I got in front she had her head in the air going to the post.

"If something had challenged on the outside I would have just been off and gone again.

"She's so brilliant early so it's hard, but if she had a bunny she'll be better chasing."

Shoals has firmed from $13 to $9 second favourite behind Catchy for next month's Group One Thousand Guineas (1600m).

Trainer Anthony Freedman believes Shoals will improve from the run and the Thousand Guineas Prelude over 1400m on October 1 would be telling in relation to Guineas aspirations.

"Her record says she's a good filly," Freedman said.

"She just gets it done. We've just got to find out now whether she gets to a mile or not.

"She has only been to 1200 metres. The Prelude will tell us where we're going."