On a brilliant weekend of racing Donnacha O’Brien was one of the stars, training his first classic winner at the age of just 21.

Fancy Blue battled hard to see off Irish compatriots Alpine Star and Peaceful to give last year’s champion jockey a win in the Prix de Diane at Chantilly, just a week after he claimed his first win of the Irish flat turf season at Limerick.

O’Brien said: “There is so much pressure and a lot of work goes into this but the feeling is great. Pierre [-Charles Boudot] is a very good jockey and I told him to do whatever he wants. The straight felt like a lifetime!”

At 21, Donnacha is a classic-winning trainer four years before his brother Joseph was and six years before his father Aidan.

But it was a case of business as usual for the latter at Epsom on Saturday when he recorded two more classic wins with Love and Serpentine.

The former was an impressive winner of the Oaks, coming off a fast pace to hammer her rivals by nine lengths. She could be the three-year-old of the summer now and with a fillies and age allowance, could be very difficult to beat in some of the flagship races, perhaps most notably the Arc where three-year-old fillies have a very good record.

Serpentine’s Derby was a remarkable race. Ridden by former Irish Champion apprentice rider Emmet McNamara, Serpentine rushed to the lead inside the first furlong, was allowed a significant gap by the chasing pack and was never caught, with five and a half lengths to spare at the finish.

McNamara said: “I think I got a little bit of a freebie. I had a huge amount of confidence in the horse having spoken to Aidan during the week. All I could hear was the horse breathing. He was in a good rhythm and I couldn’t hear a thing around me.

“I didn’t want to be looking. I wasn’t sure, but I knew I was a few clear all right. It’s a bit surreal. I can’t believe it.”

Elsewhere on another action-packed weekend, dual Arc winner Enable was defeated by Ghaiyyath in the Eclipse at Sandown. The winner, trained by Charlie Appleby, had a race fitness advantage and was ridden beautifully from the front by William Buick.

Enable, reported by John Gosden as only 85% fit will now contest the King George VI and Queen Elizabeth Stakes at Ascot, a race she has won twice before.