Field Of Gold surged to a spectacular victory in the St James's Palace Stakes at Ascot.
The 8-11 favourite, under Colin Keane for trainers John and Thady Gosden, won by three and a half lengths from Henri Matisse, with Ruling Court third.
Field Of Gold had been runner-up to Ruling Court in the 2,000 Guineas, but then went on to win the Irish version and was a decisive victor here.
"Good horses make it look easy," said Keane, who replaced Kieran Shoemark on the horse after his Guineas defeat at Newmarket, and was recently appointed retained rider for owners Juddmonte.
Victory came 11 years after Field Of Gold's father Kingman won the same race.
Docklands landed the Queen Anne Stakes, while American Affair won the King Charles III Stakes.
Docklands was a dramatic winner of the opening Queen Anne Stakes as the 14-1 shot beat favourite Rosallion by a nose.
The winner, trained by Harry Eustace, just gained victory in the Queen Anne Stakes in a photo finish, despite Australian jockey Mark Zahra losing his whip in the closing stages.
"Everyone kept scaring me with the whip rules so I thought it was just as easy to throw it away at the 200-metre mark," joked Zahra.
The 100-1 shot Cairo was third, with Notable Speech fourth after rider William Buick also lost his whip and struggled to find a clear passage.
Docklands won the Britannia Stakes at the 2023 meeting before finishing second in the Queen Anne last year.
American Affair secured the King Charles III Stakes for Scottish trainer Jim Goldie's first Group One triumph.
Ridden by Paul Mulrennan, the 11-1 victor edged out Frost At Dawn by a neck.
"Funnily enough, I was pretty confident he would do it today. It's great - it means a lot," said Goldie, who has trained since 1994.
The 7-2 favourite Gstaad was an impressive three-length winner of the Coventry Stakes, with outsiders Do Or Do Not (80-1) and Coppull (66-1) second and third.
Ryan Moore led his mount down the middle of the track to give trainer Aidan O'Brien an 11th winner in the race.
Albert Einstein would have been favourite but for a joint injury ruling him out, and O'Brien paid a huge compliment to Gstaad's stablemate, saying he is "the most different horse we've ever seen. He's so quick".
Around 270,000 spectators are expected at the Berkshire track over the five days.
Ascot is confident it can cope with a week of warm weather, with temperatures expected to reach as high as 29C by Saturday.
"Thoroughbred racehorses are able to run in very hot temperatures, including in countries such as Dubai," said a course spokesperson.
"To ensure their welfare here at Royal Ascot we provide them with lots of water and ice if necessary.
"We've had days at Royal Ascot over 30C and we have a dedicated team of people to help cool the horses after they've raced."
Going conditions are described as good to to firm, with the ground watered to help with safety for runners and riders.
The course's dress code was relaxed for the first time during a heatwave three years ago, but the same is not expected to happen this week.