The Ger Lyons-trained Mustajeer (16/1), fourth last year, went three better to land the first ever £1million Sky Bet Ebor at York, beating 25/1 outsider Red Galileo.
Desert Skyline (25/1) stayed on well to be third with 16/1 shot Raymond Tusk back in fourth.
Mustajeer, tipped on these pages by our own Ben Linfoot and top commentator Simon Holt, was taking a drop in grade having been mixing in Pattern company all season and Colin Keane's mount made his class count with a fine turn of foot which got him to the front just over a furlong from the finish.
Red Galileo emerged as a danger down the stands' side under leading apprentice jockey Cieren Fallon, and Gerald Mosse weaved a path through the pack on Desert Skyline, but the winner was not for catching and, after finishing fourth to Muntahaa 12 months ago, stuck to the task well to win by three-quarters of a length.
Barsanti (25/1) was near the back early on in the race but also finished well to take fifth, while sixth went to the well-backed, Willie Mullins-trained mare True Self (14/1) who looked a big danger when making her move soon after the turn for home.
Sponsors Sky Bet were paying each-way places down to eight and the final two places went to Ben Vrackie at 8/1 and 33/1 chance Prince Of Arran.
Six-year-old Mustajeer's decisive success earned an immediate quote of 20/1 for November's Melbourne Cup.
Lyons was not present, but tweeted: "Fantastic performance by @ctkjockey & Mustajeer & my team winning the Ebor. Now I'm off out to cut the grass."
Keane said: "It's brilliant. After he ran so well last year the plan was to come back.
"He's got better with racing. Last year he was difficult to handle, but he's been better this year. He wears ear plugs.
"He is more relaxed and seems to get better with age."
Kerri Lyons, assistant to her father, said: "That's his last race for us. He's been sold to go to Australia, but David (Spratt) still owns a share. Hopefully it will be the Caulfield Cup and then the Melbourne Cup.
"That will be a dream come true and he'll do well for the new owners (Australian Bloodstock)."
She added: "His next port of call is down in Australia.
"He did that well. Colin was very happy with him."