Since causing a semi-upset in the Queen Anne at Royal Ascot, Aidan O'Brien's colt was defeated by Al Kazeem in the Eclipse and Toronado in the Sussex Stakes.
O'Brien justifiably waxed lyrical about Declaration Of War's remarkable make-up, while connections of the vanquished pair were left scratching their heads.
Eventual runner-up Trading Leather took the field along with James Doyle and 11-8 favourite Al Kazeem sat poised on his heels.
A sense of urgency appeared to envelop Doyle as he tried to wind up the pace halfway down the home straight but his old ally failed to initiate a response and Joseph O'Brien and Declaration Of War (7-1) were moving best.
The game was up for Toronado long before he encountered what would have been an unknown final couple of furlongs and Richard Hannon's colt looked a husk of his usual self as jockey Richard Hughes eased him home.
Trading Leather, the Irish Derby winner and King George runner-up, was the epitome of belligerence on the rail and threatened to get back ahead once passed but he could not quite regain enough momentum and was beaten by a length and a quarter.
"He has such an unbelievable constitution, this horse, we've never had one like him," said O'Brien.
"Every day at home he's getting better and better, which is amazing.
"He's had all these races but he never goes backwards. He's in full work all the time at home. I know I said after Ascot he'd go back in trip rather than forward, but I suppose there aren't the races for him."
Looking ahead, O'Brien said: "There's a lot (of horses) going there but he could go to Leopardstown for the Irish Champion Stakes.
"The Breeders' Cup Classic is always a dream and he's very like Giant's Causeway (winner at York and Leopardstown in 2000 before running second in America)."
Joseph O'Brien said: "I'm not sure if it was as much of a surprise to us as it was to a lot of people. A mile and a quarter on hard ground suits him lovely."
Of Trading Leather, trainer Jim Bolger said: "It was an excellent run and he'll now go for the Irish Champion Stakes."