Ouija Board put up a hugely impressive performance to claim the Vodafone Oaks at Epsom this afternoon.
Ed Dunlop's filly took up the running two furlongs out under Kieren Fallon and the 7-2 chance swept clear of 11-4 favourite All Too Beautiful in brilliant style to win by seven lengths.
Godolphin's first string Punctilious plugged on for third under Frankie Dettori.
Ouija Board was given a superb ride by Fallon to hand the filly's owner Lord Derby and Dunlop a first English Classic winner.
The champion jockey settled her in rear as Kisses For Me set the early pace, with Dettori soon taking it up on Punctilious to step up the pace.
Sundrop pulled hard under Kerrin McEvoy all the way and she soon faded out of it turning for home as Dettori kicked on.
All Too Beautiful was poised on the outside and Jamie Spencer delivered her for a winning run, but he had no answer to Fallon, who was biding his time
before throwing down his challenge.
The daughter of Cape Cross changed gears and sailed home from All Too Beautiful, with Punctilious a further three and half lengths back in third.
A jubilant Dunlop said: "We didn't know whether she would stay, but Kieren gave her a great ride, she got home well and won like a champion."
Fallon added: "She was very impressive when she won at Newmarket and we tried to get her switched off for the first half of the race today so she would get the trip.
"She never gave me any indication that she wouldn't stay and she really got home well."
Although the current Lord Derby only has the one horse in training, the family's famous black silks with white 'lucky button' and cap are historic.
Lord Derby said: "Wasn't that unbelievable? It was just so incredible.
"She was so relaxed, which was what we wanted from her with there being doubts about her stamina.
"Kieren rode her beautifully and Ed has put up a great training performance to get her here on the day.
"She is going to make a great mare and the excitement of winning is unbelievable, so I guess we'll see some more horses in training, no doubt about it."
O'Brien said of All Too Beautiful: "She ran very well, but was very green.
"She has only had two very soft races and didn't come down the hill that well, but ran a lovely race.
"We were very hopeful because we have always thought the world of her, and we are very happy. The Irish Oaks will be the next race for her."
Simon Crisford, racing manager for Godolphin, felt both Punctilious and Sundrop had failed to handle the undulations of Epsom.
He said: "We are disappointed for both fillies. Punctilious did not handle the track and Sundrop raced too freely and also didn't handle the track.
"We are disappointed, but they will be back. Many congratulations to the winner."