Prepared by Anthony Freedman, Shoals finished second in the Group I MRC Thousand Guineas at her previous start to Aloisia and was well fancied to give the older mares a run for their money.
Shoals was ridden forward from gate 10 by Dean Yendall, who won the race last year on three year-old filly I Am a Star.
He was able to repeat his performance, driving the filly to the front after turning for home and holding off all challengers to win the 1600 metre feature by a short half head over I Am Invincible mare Eckstein.
"She began well and travelled sweetly," Yendall said.
"I pushed the button a bit early, but I knew I had a 7kg pull in the weights. It was a massive effort."
Shoals has the impressive record of five wins and two seconds from seven starts with prizemoney topping $1million.
"We got confident when Aloisia won last Saturday," revealed Anthony Freedman.
"We decided to keep something up our sleeve for this race. She was incredibly tough today. There's no reason she can't win a few more Group One's."
Shoals was retained to race by her breeders Arrowfield Stud and Jonathan Munz (in whose colours she runs) and is the first foal of The Broken Shore, who was bought by Dean Hawthorne Bloodstock for $1.9 million at the Magic Millions Teeley Assets Dispersal in 2014.
A metropolitan winner by Hussonet (USA), The Broken Shore is a half-sister to Group I winners Redoute's Choice, Manhattan Rain and Platinum Scissors as well as Group III winner Sliding Cube and stakes-winner Echoes of Heaven.
The Broken Shore has been to Fastnet Rock in three seasons running and was covered last spring by Medaglia D'Oro (USA). Her current two year-old filly, a full sister to Shoals, is called Tides and will also be trained by Anthony Freedman.
The 31st Group I winner for Fastnet Rock, Shoals brought up a Group I double for her champion sire, who also tasted success at in the $1million VRC Coolmore Stud Stakes with exciting colt Merchant Navy. Click here to read about him.