The filly surged clear down the outside of the field passing the two-furlong marker and the result was never in doubt thereafter, with Seb Sanders’ mount sailing past the post with three and three-quarter lengths in hand.
Musidora also-ran Moonstone came from even further back with her challenge to take second, with John Oxx’s Katiyra overcoming her inexperience to reward each-way support in third.
Beckett came agonisingly close to carrying a big race back to Whitsbury when Penkenna Princess was just touched off in the Irish Guineas three years ago, but nothing prepared him for the moment of glory.
“This is just amazing, you do not expect to win races like this when you start training,” he said. “When she hit the front I was looking around for dangers and willing her on, it is just an amazing feeling.
“At no time was I ever confident, but I thought we would run a race. Now we can say we have won a Classic and if I go skint next week it doesn’t matter.”
Beckett’s daughter of Hernando won her sole start as a juvenile when claiming the scalp of Vodafone Derby candidate Doctor Fremantle in October.
And her huge starting price was no doubt influenced by her failing to reel in Miracle Seeker in the Lingfield Oaks Trial on her prep for Epsom.
“She is the most extraordinary filly. She absolutely hosed up at Salisbury and I thought that perhaps Doctor Fremantle wasn’t on top of his game and we weren’t sure, but subsequently that form is rock-solid,” Beckett continued.
“I wasn’t going to run at Lingfield and it was fast ground, but they did a great job watering. The race there just didn’t work out for us.
“She worked shockingly last week and I said to my head man that we had to work her again on Saturday as we couldn’t go to the Oaks after that.
“We switched gallops and worked her back towards home and she worked well. It then rained all week and we were chuffed to bits with that.”
Aidan O’Brien was mob-handed with Moonstone finishing best of his six runners.
He said in the immediate aftermath: “I’d be lying if I was to give you an accurate reflection of how they have all run right now, but I can tell you the second filly has run a great race.”
Oxx said of Katiyra: “She ran well. She was impeded a little bit coming down the hill when she was caught up in traffic.
“She stumbled crossing the road, which maybe cost her second, but then she quickened up well, despite her inexperience.
“I expect she’ll run next in the Irish Oaks in five weeks’ time.”
Roger Charlton is also targeting the Curragh Classic with fourth home Clowance, who he added failed to handle the track.
Pat Smullen reported Chinese White stopped very quickly as she dropped out to ninth, while Kevin Manning added that fifth-placed 5-2 favourite Lush Lashes “didn’t stay, full stop.”