The brilliant dual Oaks winner came from a different parish to collar Irian under an ice-cool Ryan Moore.
Ed Dunlop’s three-year-old was adding to last month’s similarly impressive triumph in the Queen Elizabeth II Commemorative Cup in Japan.
Fellow British raiders Sri Putra and Glass Harmonium finished a respective 11th and 12th, having failed to show their best form.
The same cannot be said of Snow Fairy, who was truly outstanding.
Reassuringly for her supporters, she will now stay in training as a four-year-old.
Although Packing Winner – the eventual third – teed up a generous pace, Moore was content to hunt, rather than chase, towards the rear of the field.
Even heading into the final one and a half furlongs, the Intikhab filly still had at least seven horses in front of her.
But Moore’s sangfroid patience was vindicated as Snow Fairy suddenly hit her stride and weaved into contention.
Irian still looked to have pinched the Group One encounter under Brett Prebble, but Moore came with an exceptional late surge to take the glory by a neck.
Last year’s winner, Vision D’Etat, finished fourth in the hands of Olivier Peslier.
Snow Fairy has now won four races at the highest level, taking her career earnings to over £2m.
Dunlop said: “All credit to my staff who have worked so hard on an amazing day for the yard. I thought it was too close between races to run her after Japan and she didn’t gallop for seven weeks.
“To do it against the colts for the first time in her life puts her down as an exceptional horse, there can be no doubt over that.”
There was no fairytale swansong for Paco Boy as Richard Hannon’s star miler finished last in the Cathay Pacific Hong Kong Mile, which was claimed by Beauty Flash.
Hamstrung by a lifeless pace and an allegedly unfavourable draw, Ryan Moore’s mount faced a tall order in attempting to circumnavigate the field. He nonetheless failed to show his customary late burst and was never a factor. The five-year-old is now set to be retired to stud.
Ballydoyle’s Beethoven, partnered by Colm O’Donoghue, beat home only Paco Boy in the 13-runner field.
Mastery, the 2009 St Leger winner, scooped another huge prize when emerging victorious in the Cathay Pacific Hong Kong Vase.
Godolphin’s four-year-old has this season been used sparingly, and clearly had fitness on his side in defeating fellow British raider Redwood.
Always close to the pace under Frankie Dettori, the Saeed bin Suroor-trained colt really got going once Mighty High took them along into the home straight.
Mastery gained a clear-cut advantage two furlongs from home – a lead he never looked like relinquishing.