Pether's Moon saw off French raiders Dolniya and Flintshire to claim a shock victory in the Investec Coronation Cup at Epsom.
Alain de Royer-Dupre's Dolniya was a warm order for the Group One contest as the 8-11 favourite, making her first appearance since a brilliant display in the Dubai Sheema Classic in late March.
Christophe Soumillon dictated matters from the outset at the head of affairs and looked set to collect when seeing off last year's runner-up and old foe Flintshire heading inside the last quarter-mile.
However, Pat Dobbs would not give up aboard 11-1 shot Pether's Moon and Richard Hannon's charge quickened between the raiding party close home and got up to beat the market leader by a neck.
Andre Fabre's Flintshire, who was second to another compatriot in Cirrus Des Aigles 12 months ago and chased home Dolniya at Chantilly and Meydan earlier this year, was not far away in third.
Sheikhzayedroad was last of the four runners.
Dobbs, riding his first Group One winner, said: "He was very good. He's loads of ability, but he pulls up when he gets to the front.
"Even though I got there late, I could feel him pulling up in the last 50 yards, but he's got plenty of class.
"He's run some good races, he obviously handled the track and he loves fast ground."
Hannon said: "I must admit I didn't see that coming. His last run was very moderate.
"He's been around the circuit this horse and probably deserves a bit more credit than he gets.
"John Manley, his owner, always tries him pretty hard. This was his entry and well done to him.
"John has really enjoyed this horse, he might go to Melbourne (Melbourne Cup), I don't know.
"Pat has given him a super ride. Hughesie (Richard Hughes) has ridden some lovely races on him as well, but he really goes for Dobbsy."
