John Gosden's Richard Pankhurst improved significantly on his debut run to secure the Listed Chesham Stakes, the opening race of the final day of Royal Ascot.
The 10/1 shot, ridden by William Buick, finished only fourth on his only previous run at Newmarket last month but he turned the competitive seven-furlong contest into a rout in the closing stages.
American raider Crown The Kitten set solid fractions up front but he was a spent force more than three furlongs from home and eventually got into a barging match with Wesley Ward stable companion Cordero, who failed to make much headway on the leaders afterwards.
Two furlongs out, Toscanini breezed to the front and looked like going on to win well for Mick Halford and Shane Foley, with the eventual winner still some way off the pace and already feeling the warmth of Buick's whip.
But once he was switched outside and got a clear run, the hooded son of Gosden yard favourite Raven's Pass, picked up well and by the line he had bounded into a near four length lead.
Toscanini, still a maiden, kept on to claim second at 4/1 with 15/8 favourite Dick Whittington close behind in third ahead of Nafaqa, who showed immense promise in the closing stages after being slowly away.
The winner was Gosden's fourth of the week and a third for Buick, who said: "He gave me a very nice feel.
"I spoke to Robert Havlin before I came here and he said he was green first time, so he always knew he was going to come on a lot.
"At halfway he came good and it was just a matter of trying to get out in time. He's won going away at the finish and was by far the best horse in the race."
Owner Rachel Hood, Gosden's wife, said: "I have obviously got to thank my husband, William Buick and all our staff and the horse.
"Overwhelmingly, I'm speechless. He's exceeded my expectations, but the trainer usually doesn't fill me in on what might possibly happen!"
"It's very exciting as the man who led this horse up and looks after him rode Raven's Pass every day," said the trainer.
"Saturday of Royal Ascot is great because all of the families come - it's the hugest crowd and they come and have a picnic. We have managed to get 40 of them stuffed in the winner's circle here.
"With all of these owner/breeders, Rachel is trying to keep up with Lady Lloyd-Webber and Lady Bamford but she has a long way to go.
"It's beyond exciting to have a horse that Rachel bred at Pantile Stud near Ely on the Fens. It's unusual to breed a horse in the Fens but they can grow a good horse there - they grow a lot of good vegetables, so why not a horse?
"We are very lucky actually because I ran him to come here and I have been planning it for three months. I thought that if he won first time out, we would pop him in the sale on Monday night. So he would have been sold, won for someone else and I would probably be an ex-husband."
Sky Bet introduced the winner at 16/1 for next year's 2000 Guineas at Newmarket.