Trip To Paris denied the Irish raiders when coming with a power-packed late run to claim the Betway Chester Cup.
Trained by Ed Dunlop and ridden by Graham Lee, the four-year-old (10-1) arrived with a last-gasp charge from the outside of the field.
Tony Martin's Quick Jack finished second as the 4-1 favourite, while the Dermot Weld-trained Zafayan was third.
Lee said: "He was hanging badly left, and I ended up dropping the reins along the straight.
"He's always travelled well and he showed at Ripon he's got a turn of foot."
The landscape of the race did not alter too much until the final five furlongs when the front-running Buthelezi faded out of the picture.
John Reel was always to the fore and gained a slight advantage, but the Irish duo were hot on his heels and ended up jousting for top honours two furlongs out.
Just when it looked like the versatile Quick Jack had the edge over Zafayan, Trip To Paris suddenly darted into contention and ended up scoring by three-quarters of a length on his first try at beyond two miles.
Gabrial's King completed the minor positions in fourth place.
Dunlop, whose inmate was bringing up a hat-trick following victories at Lingfield and Ripon, said: "The horse was amazing.
"It's the first time he's run at that trip - he's been a revelation. I made the strange entry and he's won.
"He's a mile-and-a-half to a two-mile horse. He quickens, and I think that's made the difference.
"I've always wanted to win this race. It's very hard to do it, so it's a great day."
Connections could now consider supplementing Trip To Paris for the Gold Cup at Royal Ascot.
"This is a similar type of horse to Red Cadeaux and he's improving all the time," said Dunlop.
"We might supplement him for the Gold Cup, but I think we'll wait and see.
"This horse relaxes. He wore blinkers as a colt (now a gelding) because he was lazy, but he can stay this far and he's got a good turn of foot.
"We don't have to do anything with him at home now as he's got a wonderful temperament. He's become a man this year."
On a possible trip to Australia for the Melbourne Cup in the autumn, the Newmarket handler said: "He's got to rise in the weights to get into the Melbourne Cup this year.
"Maybe we'll take two (Trip To Paris and Red Cadeaux) to halve the expense."