Educator finished second as he became the first runner for the King in the famous royal silks at Salisbury.
While His Majesty has previously had runners in the colours he shared with the Queen Consort when they were the Prince of Wales and Duchess of Cornwall, it is the first time the famous purple, red and gold silks took to the track in his name.
The William Haggas-trained Educator was the first horse to race in the colours since Improvise was beaten a short-head at Epsom on September 8, the same day the Queen died at her Balmoral estate in Scotland.
Once viewed as a Derby hopeful, the three-year-old had been off the track since winning a Newmarket handicap back in April but was sent off the 11-10 favourite on his return in the Radcliffe & Co Handicap.
Educator travelled well enough through the early part of the race, but with three furlongs to run Marquand was pushing along to keep up as Okeechobee cruised into the lead.
Roger and Harry Charlton’s runner went on to win by four and a quarter lengths in impressive fashion, with Educator staying on for minor honours.