Italian challenger Electrocutionist finished strongest to win the Juddmonte International on day one of the Ebor meeting at York.
The 9-2 chance, ridden by Mick Kinane, came from the rear of the field in the straight to pip his rivals on the line.
Aidan O'Brien's Ace set the early pace but found himself struggling in the final stages.
Japanese challenger Zenno Rob Roy came through well but he was forced to give second best to the winner.
Sir Michael Stoute's Maraahel finished back in third.
"I probably gave him a shade too much to do, he was just struggling to pick up on the ground," admitted Kinane after the win.
"I always thought I was going to get to them, but just at the two furlong pole I hit a bit of a flat spot. Once I got to the Japanese horse's quarters I always knew I'd get there.
"I loved this horse when I rode him last week and I was very pleasantly surprised with the feel he gave me.
"I said he was a proper Group One horse."
It was the second big win of the day for Kinane who came through late on Hard Top to win the Great Voltigeur Stakes at York.
The Sir Michael Stoute-trained horse, who went off at 6-1, got through in the final stages to overhaul the favourite The Geezer.
Richard Quinn had brought The Geezer to the front within the last three furlongs as he stretched for home.
But Kinane and his mount dug deep and battled to the line for victory in only his third start.
Juddmonte International
1. Electrocutionist (M J Kinane) 9-2
2. Zenno Rob Roy (Y Take) 4-1
3. Maraahel (R Hills) 8-1
7 ran. Dist: nk, hd
Great Voltigeur Stakes
1. Hard Top (M J Kinane) 6-1
2.The Geezer (T Quinn) 6-4 Fav
6 ran. Dist: ½, ½