Santa Barbara gained her second top level success when running out a ready winner of the Beverly D. Stakes at Arlington on Saturday.
The highly regarded filly had been sent off as favourite for both the 1000 Guineas at Newmarket, finishing fourth, and the Epsom Oaks where she was fifth, some 20 lengths behind the winner Snowfall.
Santa Barbara got closer in the Pretty Polly Stakes, going under by just a neck at the Curragh, before gaining a breakthrough top-level success last month in the Grade One Belmont Oaks.
She was sent off at even money to follow-up that victory against her elders in the Beverly D. Stakes over an extended nine furlongs.
Ryan Moore settled her in behind the early pace before pulling wide around the final turn and he didn't need to get serious with the daughter of Camelot who pulled readily clear under hands and heels to win by three lengths from Mean Mary.
It was a third victory in the race for Moore following Dank and Euro Charline and a first for trainer Aidan O'Brien.
"This is a beautiful racetrack, a beautiful turf course," Moore told www.bloodhorse.com.
"I feel very honoured to have been allowed to come here.
"She was very straightforward. She's an improving 3-year-old. I can't speak for the owners but I would assume she might be back. Perhaps for the Breeders' Cup," Moore added.
O'Brien and Moore were out of luck in the Mr D. Stakes (formerly known as the Arlington Million) with Armory who could only finish sixth off a slow pace.
Space Traveller, owned by Clipper Logistics and ridden by Danny Tudhope, was fourth on his first start for Brendan Walsh.