Defending champion Nathaniel was denied victory by a nose as Danedream won the King George VI and Queen Elizabeth Stakes at Ascot in dramatic fashion.
The 9-1 shot, ridden by Andrasch Starke and trained by Peter Schiergen, pipped Nathaniel in the final stride.
It was a return to form for last year's Prix de l'Arc de Triomphe winner, who became the first German horse to triumph at the Group One feature.
Aidan O'Brien's St Nicholas Abbey finished well to claim third.
Nathaniel, who won the Coral-Eclipse at Sandown just two weeks ago, had looked set for victory when quickening into the lead in the home straight but Danedream had sufficient momentum to snatch victory on the line.
She became the first filly to win the race since Time Charter struck as a four-year-old in 1983.
Starke told BBC Sport: "It was close - it was very tight - but I had a good feeling. She fought hard and it's definitely the biggest moment in my life."
KING GEORGE VI AND QUEEN ELIZABETH STAKES, Ascot
1 Danedream 9-1
2 Nathaniel 5-2
3 St Nicholas Abbey 5-1
4 Reliable Man 20-1
5 Sea Moon 6 Dunaden 7 Brown Panther 8 Deep Brilliante 9 Masked Marvel 10 Robin Hood