Frankie Dettori and the Queen's trainer Andrew Balding gained a fitting win as racing paid tribute to its greatest supporter.
The pair combined in the Group Two Coral Champange Stakes, the first race on St Leger day, with Chaldean (2-1). Dettori and Balding both shared many successes with the Queen, whose horses sported the famous scarlet, purple, red and gold braided silks.
They joined their industry colleagues in a two minute silence before racing, at the track where the Queen won the afternoon's feature race, the St Leger, in 1977 with Dunfermline.
Dettori, wearing a black armband along with his fellow weighing room professionals, returned to muted celebrations after Chaldean defeated his two rivals by three-and-a-half lengths.
The 51-year-old, who partners Haskoy for the colt's owners Juddmonte in the St Leger, said: "There is a bit of an empty mood in the weighing room. I didn't jump off (usual celebration after riding a winner) out of respect. We're carrying on and having to deal with it, but it's still fresh in the memory.
"We're going to miss her a lot."
The Balding family have a long association training for the Queen and the current Kingsclere licence-holder successfully prepared King's Lynn for the Group 2 Temple Stakes at Haydock in May.
It was one of Her Majesty's final big winners during a lifelong association with horse racing. During the 70-year reign, her thoroughbreds were successful on 24 occasions at Royal Ascot and she had five Classic triumphs.
Balding said: "Today's result will lift the mood a little bit at home but a big hole has been left in everybody's life. We have been so privileged to have worked for her and to have known her for so long. It's a great loss."
You can leave your tributes to Queen Elizabeth II here
The St Leger, a final Classic race of the Flat season, was postponed from Saturday to Sunday as a mark of respect following the Queen's death. A tribute to the late monarch played out to Doncaster racegoers on the big screen and they sang the new British national anthem after observing the silence.
The extended nine-race card comes on a day when thousands of people lined the route Her Majesty's coffin is taking from Balmoral to the Palace of Holyroodhouse in Edinburgh.
Racing fixtures scheduled for September 19, the date of the Queen's funeral, have been cancelled.
* This weekend, the Daily Mirror and Sunday Mirror celebrate the life of Her Majesty the Queen with a commemorative special filled with all the key moments from Britain’s longest reigning monarch. Be sure to pick up your copy of the Daily Mirror and Sunday Mirror to get both pullouts.