Monterosso led home a Godolphin one-two in the Dubai World Cup as he stormed clear of stablemate Capponi to win the world's richest race in the hands of jockey Mickael Barzalona.
Barzalona was stood high in his stirrups and he saluted the crowd as the Mahmood Al Zarooni-trained 5-year-old approached the winning line.
The success capped a fine training performance from Al Zarooni, who also trained the runner-up. The pair were formerly trained by Mark Johnston.
So You Think, representing Aidan O'Brien, failed to quicken in the straight and could manage only fourth under the trainer's son Joseph. Planteur, trained by Marco Botti, made good late headway to snatch third.
Sheikh Mohammed, the mastermind behind the Dubai World Cup meeting, told the Racing Post: "It is a very special night and I'm very, very pleased. Mark Johnston did a good job with this horse."
Transcend and Capponi made most of the running during the early stages of the race. So You Think, sent off the 5-4 favourite, was narrowly in behind the leaders.
Monterosso was positioned in behind under Barzalona as Game On Dude, ridden by Chantal Sutherland, was forced to make ground on the outside of the field.
Capponi attempted to take a length or two out of his rivals as the home straight beckoned and he seemed to have the measure of So You Think but he could not cope with Monterosso, who sprinted past and established a clear lead.