The 7-4 favourite Roaring Lion and jockey Oisin Murphy held on for victory in the Coral-Eclipse at Sandown after a lengthy stewards' inquiry.
The pair had crossed the line a neck ahead of 2,000 Guineas winner Saxon Warrior and Donnacha O'Brien (9-4).
However, the two horses had come together in the final stages of Saturday's race.
But the stewards ruled that the result would stand, giving Murphy his first Group One winner.
Hawkbill made the early running from Forest Ranger, but the older horses had no answer to the two three-year-olds, who dominated the finish.
Roaring Lion's trainer John Gosden, who had seen his horse finish third behind late absentee Masar in last month's Epsom Derby after victory in York's Dante Stakes, was delighted with Murphy's performance.
"He rode him beautifully and very coolly," said Gosden. "He got too far back, he knew that, and he didn't hurry to get back. It was a very good ride and I'm thrilled.
"He [Murphy] deserves it [a first British Group One win]. He did very well to stay as cool as he did."
Murphy said: "Whenever a horse shifts off a line or anything small in a race, the stewards look into it.
"My horse has caused very little interference, if any, and clearly he was the best horse in the race."