Mishriff won the Juddmonte International by a decisive margin at York's four-day Ebor Festival in front of nearly 20,000 spectators.
Mishriff, ridden by David Egan, went into the race as favourite and was followed by Alenquer in second and Love in third.
The four-year-old horse, owned by Prince Faisal, also won Group One races in Saudi Arabia, Dubai and France.
Trainer John Gosden said Mishriff is the "finished article".
It was the fastest-ever running of the one-and-a-quarter-mile race, as Mishriff won by six lengths.
"He's come to his very best and done nothing but improve in his last few races," added Gosden.
He has not ruled out taking Mishriff to the Breeders' Cup in November, where he was the last English trainer to win the classic race with Raven's Pass in 2008.
"At a mile and a quarter he's a brilliant horse," said Gosden. "He's done nothing wrong and has now come to his very best.
"This is the race we've talked about since last summer before making him a stallion for Europe.
"I would be inclined to look towards the Arc and Champions Day [next]."
Gosden also won the Juddmonte in 2018 with Roaring Lion, ridden by Oisin Murphy.
The Juddmonte, one of three Group One races in the festival with the Yorkshire Oaks on Thursday and Friday's Nunthorpe Stakes, is often won by the highest-rated flat horse at the end of the year.
Love, who won last season's 1,000 Guineas and Oaks and finished third in the Juddmonte, was the sole representative of trainer Aidan O'Brien in the big race after hot favourite St Mark's Basilica was withdrawn through injury.
The York meeting, which has 28 races and a total prize money of £4.7m, will finish with Saturday's Ebor - the richest handicap race staged on the flat in Europe.