Owner Anthony Oppenheimer took a £75,000 gamble in supplementing his unbeaten Dante winner, but his colt handsomely rewarded his faith with a blistering display that marked him out as the standout middle-distance three-year-old colt, and a potential superstar of the sport.
Many of the questions coming into the race revolved around Golden Horn's ability to see out the mile and a half of the Derby trip, with his owner initially keener to go for the French equivalent over a shorter trip.
But Gosden persuaded his owner to take the chance, prepared the horse to the minute and then handed him over to Dettori, who settled his mount towards the rear off a searing early gallop and guided him through horses to win in the manner of a horse who appreciated every yard of the trip.
"It's such a thrill, it's amazing," said Oppenheimer, who also bred the winner. "I can't really believe it. I have to thank the staff at my stud, everyone there has worked so hard."
THE WINNING MOVE
Turning into the home straight Golden Horn was some ten lengths off the leader Hans Holbein, with just three of his 11 rivals behind him. With three furlongs to run Dettori angled to the outside on the 13-8 favourite and set about closing the gap but the response was not instantaneous.
With two furlongs to run he still had five horses to pass with his progression owing more to others fading than any burst of acceleration. That was still to come.
No sooner had William Buick hit the front with a decisive move on the 4-1 second favourite Jack Hobbs than Dettori came over the top of him on Golden Horn and surged clear for a three and a half length victory over his stablemate, with a further four and a half lengths back to William Haggas's Storm The Stars, who fared best of the non-Gosden-trained runners.
On his one-two, the trainer said: "Golden Horn was quite keen early and took Frankie on. The last thing I said to Frankie was ride a cool race and he rode a cool race - he waited and waited. He's a proper horse.
"Jack's run a great race and was beautifully balanced down the hill by William and ran a belter. All being well he will go to Ireland."
DOUBLES ALL ROUND
Golden Horn followed the same route as John Gosden's previous Derby winner Benny The Dip, who also came via the Dante in 1997. Frankie Dettori's previous Derby winner, Authorized in 2007, also came via the Dante and was the last horse before Golden Horn to do the double.
"I can't believe it! He was brilliant! I was just a passenger," said Dettori. "He hit a flat spot and I thought I can't get him going but then he flew.
"In the last 100 yards I couldn't believe I had won the Derby again. I have to pinch myself. I can't get to the bottom of this horse and I couldn't pull him up at the end of the race. He is an unbeaten Derby winner - what more can you say?!"
Golden Horn was a late addition to the Derby, with connections paying £75,000 to run five days ago. He picked up £813,221.40 for winning, a much better return than his odds of 13-8. Perhaps even more valuably can now be called a Derby winner when going to stud.
Kris Kin, in 2003, is the only other Derby winner to have been supplemented. Success Days, the other horse supplemented at the five-day stage for this year's race, finished last.
Extract From Racing Post