Docklands handed Harry Eustace his first Group One success and star three-year-old Field Of Gold lit up the turf on a bumper day one of Royal Ascot on Tuesday.

Eustace celebrated the biggest moment of his career with his brother David, who has made a strong impression in his first season as a handler in Hong Kong, after Docklands prevailed in a thrilling finish to the Group One Queen Anne Stakes (1,600m).

Starting a $14 chance, Docklands settled in the back half of the field. Despite Australian rider Mark Zahra dropping his whip at the 200m, the galloper ran on strongly to hold on by a nose from $2.8 favourite Rosallion. Cairo ($60) was almost two lengths behind in third.

“I have lost my voice. That was pretty sweet,” Eustace said after Docklands went one better than in last year’s Queen Anne.

“It was tough watching and the photo was tough. I wasn’t happy with the pace early on. Docklands did his usual thing, just stepped slow and I was cursing him to be honest, but he is just an absolute star.”

Jockey Colin Keane hailed Field Of Gold “the best horse I’ve ever sat on” after John and Thady Gosden’s outstanding colt turned the Group One St James’s Palace Stakes (1,600m) into a one-act affair.

The raging $1.6 favourite powered home from second last to bolt in by three and a half lengths, boosting his record to five wins from eight starts.

“Good horses make it look easy,” Keane, Juddmonte’s new number one rider, said. “I am fortunate enough to be riding him and, at this moment, he is the best horse I’ve ever sat on.

“I’m in a very privileged position. I’ve been lucky enough to join this team. It is a very new relationship and to get a horse like him so early on is amazing. I’ve had nothing compared to this in recent years, so it’s a very special day.”

American Affair won Tuesday’s other Group One, the King Charles III Stakes (1,000m), for trainer Jim Goldie and jockey Paul Mulrennan.