Tominator sprang a surprise for veteran trainer Reg Hollinshead and apprentice Paul Pickard in the John Smith's Northumberland Plate at Newcastle.
Last year's winner Overturn made another brave attempt to make all the running but was swallowed up by the field in the last couple of furlongs.
Totally unexposed at the trip, it was 25-1 shot Tominator who surged home at the end of the two-mile stamina test.
Montaff (18-1) was beaten by a length and three-quarters in second.
Deauville Flyer (8-1) was another two and a half lengths away in third and Petara Bay (40-1) fourth.
Andrew Hollinshead, assistant trainer to his 87-year-old father Reg, said: "It is great to win a big one. We always knew he had plenty of talent and he's shown he has plenty of stamina today.
"I wouldn't say he was backward as he actually won a nursery at Catterick over seven furlongs as a two-year-old.
"We lost our way at three as he ran at Haydock as Darryll Holland told us he didn't stay a mile and a half. That threw us off track for a while.
"We took him to France last winter and he was unlucky not to win out there. I have to give a mention to Tony Culhane, who was unable to ride today.
"He said all the horse wanted was holding up off a good pace and he was right.
"I'm not sure where we'll go now as he's going to go up handicap-wise. I'm not sure there will be many handicaps left for him. I would think he'll go jumping at some stage."
Misty For Me upstaged Midday in remarkable fashion when making all the running to land the Stobart Ireland Pretty Polly Stakes at the Curragh.
The Irish 1,000 Guineas winner bounced back from a disappointing run in the Investec Oaks with a spectacular victory in the mile-and-a-quarter feature race.
Seamie Heffernan soon had the Aidan O'Brien-trained filly out in front from Claiomh Solais with Midday settled in third place by Tom Queally.
Misty For Me (100-30) was brought down the centre of the track and showed no signs of stopping as she bolted up by six lengths from the 1-3 favourite, who in turn was well clear of Chrysanthemum in third.
Newcastle Northumberland Plate (1505) result:
1 Tominator (P Pickard) 25-1
2 Montaff (J H Bowman) 18-1
3 Deauville Flyer (T Eaves) 8-1
4 Petara Bay (Jim Crowley) 40-1
Non Runner: 12
Curragh Pretty Polly Stakes result:
1 Misty For Me (J A Heffernan) 10-3
2 Midday 1-3 Fav
3 Chrysanthemum 16-1
Non Runner: Snow Fairy