Bye Bye Baby is ridden out by Seamie Heffernan© Photo Healy Racing
Bye Bye Baby made all to land the feature at the Curragh this afternoon, the Group 3 Plusvital Irish EBF Blue Wind Stakes.
Successful in Listed company last year, the daughter of Galileo disappointed on her return to action at Navan last month, finishing eighth in the Salsabil Stakes when favourite.
Sent off at 11/4 this afternoon, she was sent straight to the front by Seamie Heffernan (riding a pound overweight).
She was ridden from two furlongs out, and kept on well under pressure from there, going on to score by two lengths.
The even money favourite Jaega was ridden from over a furlong out, but she couldn't reel in the winner, and had to settle for second under Leigh Roche for Dermot Weld.
"You'd be delighted with that and she came forward lovely from Navan," said O'Brien, who was completing a double on the card having won the opener with Land Force
"She's a very straight-forward filly and I couldn't be happier.
"She'll go to Epsom next (for the Oaks). She's very straight-forward, very uncomplicated and stays well. She's a very well bred filly too.
"On their first runs I'm never surprised. Obviously we've seen the improvement can be out of this world sometimes.
"When they start off, they start off, and you just want them to progress. The first day is just the start."
On the size of his teams for the Oaks and Derby he added: "We'll have to keep going away and see what happens. The lads will decide how many they want to run.
"If they are there we'll let them run. We'll all learn together because really from the trials you don't know. You don't know what is a good trial or an ordinary one so we'll let them in there together and find out together.
"James Cook and Zabriskie will go to the Dante.”
On his Derrinstown Trial runners, O'Brien added: "They've all come forward. The Pentagon has moved up a good bit and it will be interesting. You'd be very happy with what he's done."
Paddy Power go 14/1 (from 33s) about Bye Bye Baby for the Epsom Oaks.
Additional reporting by Gary Carson