Outstrip, trained in Newmarket for Godolphin by Charlie Appleby and ridden by Mike Smith, narrowly beat Aidan O'Brien's Giovanni Boldini to win the Breeders' Cup Juvenile Turf at Santa Anita.
Bobby's Kitten set a blistering early pace and swung into the straight still with an advantage but with Ryan Moore and Giovanni Boldini in hot pursuit.
Dundalk winner Giovanni Boldini got the better of Bobby's Kitten, but Mike Smith was all the while winding Dewhurst third Outstrip up and once engaging top gear he mowed the front two down close home for a scintillating success.
Afterwards Ryan Moore said of Giovanni Boldini: "We had a good race and a good trip, saving ground. Maybe a little bit more experience would have helped him. I did see the winner coming and I wasn't surprised at that."
O'Brien also saddled the unplaced Wilshire Boulevard and his rider William Buick added: "He travelled in the ground and my plan was to follow Ryan but something came back at me on the bend and took me out of the race, otherwise I think I would have been in the first five."