Harzand produced a blistering turn of pace to win the Derby under Pat Smullen after concerns that the colt would not run in the Classic at Epsom just an hour before the start.
The Dermot Weld trained three-year-old spread a plate on the morning of the famous race on the Downs in Surrey and was rated as 60-40 to run.
Aga Khan-owned Harzand was passed fit and the 13-2 shot clearly felt the benefits of having his foot iced, charging to victory by one-and-a-half lengths ahead of fast-finishing favourite US Army Ranger - ridden by Ryan Moore.
Smullen produced a brilliant ride to steer the son of 2009 Derby legend Sea The Stars to a third victory out of three this year to land a huge pay-day in the richest race ever run in Britain, with prize money of £1.325million at stake.
Irish jockey Smullen told Channel 4 Racing: "He dug in. I could sense Ryan [Moore] coming, and I saw US Army Ranger's white face, but this horse responded."
US Army Ranger was backed in to 7-2, but the Aidan O'Brien trained favourite was unable to get past the impressive Harzand, with stablemate Idaho completing an all-Ireland top three.
Wings of Desire was unable to give John Gosden and Frankie Dettori a second successive Derby victory, finishing fourth a year after Golden Horn's success.
Port Douglas set the pace and went five lengths clear before being caught after the turn at Tattenham Corner, with Harzand emerging from a field of 16 to bolt up in the 237th running of the prestigious race.