Mick Channon's Chilworth Icon ran out a narrow winner of the Investec Woodcote Stakes at Epsom under Martin Harley.
The trainer-jockey combination enjoyed their first Classic success with Samitar in last weekend's Irish 1000 Guineas and struck again with this 12-1 shot.
The juvenile was being strongly pressed by the more fancied Heavy Metal as the winning post approached, but Chilworth Icon won the argument by a short head, while hot favourite Euxton Hall was slowly away and never threatened to land a telling blow.
Harley said: "He'd been running good races over five furlongs, but the step up to six was definitely the key. I said to the boss he was a horse we might not get to the bottom of because he's always improving.
"I don't think the track suited him ideally and coming round the bend he ran a bit wide, but he'll come on again for this and he's a nice horse."
Channon added: "I'm delighted for everyone, including Martin. He was a great apprentice last year, when he won on some moderate horses, and he's now getting due reward.
"It's a worry sometimes bringing juveniles here, but ours tend to do well. He really wanted to win. He couldn't handle the track, but he's got a great attitude and managed to scramble home. The Chesham (at Royal Ascot) was the plan before today and it still is. The extra furlong should suit."
Kieren Fallon needed all of his renowned strength in a finish to get 10-1 shot Fiery Lad home in front in the Investec Zebra Handicap.
Luca Cumani's course winner stayed straight and true in the final furlong to nail A Boy Named Suzi right on the line, with a head the official winning margin.
The concluding Investec Out Of The Ordinary Handicap went to the Robert Cowell-trained 9-1 shot Lui Rei, who defied top-weight in the hands of Jim Crowley.