As well as her win in the Give Thanks Stakes on her latest start, the third-year-old filly had shown her class when third to Enable in the Irish Oaks, which stood in her good stead for this contest.
Spanish Steps set the pace but was swallowed up in the final furlong as the race opened up.
Pat Smullen got a good tune out of Dermot Weld's charge and the 9-10 favourite took the prize by three-quarters of a length. Exemplar finished strongly for second place.
Smullen said: "She's a filly that's a bit keen and we've spent a lot of time to get her to relax.
"She was third to Enable in the Irish Oaks and had a good win in Cork. I thought it was a very good performance against the colts today.
"She's a tough filly and improving. She'll be a lovely mare next year."
Weld said: "She's very good, she has courage and is a typical stayer with speed.
"She ran a super race in the Irish Oaks behind Enable, which shows how good Enable is.
"The Group One Fillies & Mares Stakes on Champions Day at Ascot (October 21) is the obvious follow-up. She's in the Prix Royallieu on Arc weekend, but Ascot is most likely. It's a race I've been fortunate enough to win before."