Portrush took the first small step towards emulating her half-sister Enable after striking gold at the second time of asking at Yarmouth.
Having finished second on her debut at Newbury last month, the John Gosden-trained daughter of Frankel, who shares the same dam as the dual Prix de l'Arc de Triomphe winner, went one better in the Download The At The Races App Maiden Stakes.
Racing in midfield for much of the mile-and-a-quarter contest, the 11-10 favourite steadily worked her way into contention before being pushed out under hands and heels by Robert Havlin to get up in the closing strides and prevail by a neck from White Mountain (5-1), with Tanita (2-1) in third.
Thady Gosden, assistant to his father, said: "She ran very well at Newbury and has come on nicely for the run. There was a bit more pressure today. She tightened up in the finish, but she seemed like she would have been there if he had asked for her.
"Rab gave her a lovely hands and heels ride and he didn't rush into it. He didn't go for her at all, which was good to see.
"She will probably be a mile-and-a-half filly in time, but we will see if we leave her at that trip for one more start. I don't think we will be chucking her into stiffer competition yet. She is probably one to take time with a little bit and build her up gently.
"She has done nothing wrong so far, but it might be a bit unfair to start comparing her to Enable at this point. She is very genuine and very honest and always wants to try for you."
All six of dam Concentric's progeny to reach the racecourse have now recorded wins.
Watch live coverage of the Juddmonte Irish Oaks meeting at the Curragh on RTÉ2 and RTÉ Player on Saturday from 6-8pm (Irish Oaks at 7.15pm).
