Ryan Moore produced a fine waiting ride on Hillstar to win the King Edward VII Stakes at Royal Ascot.
Investec Derby fourth Battle Of Marengo was sent off the 10-11 favourite for the Group Two over a mile and a half and jockey Joseph O'Brien made a bold bid for home.
The race looked over as Battle Of Marengo was a good three lengths clear of the pack entering the final furlong, but Hillstar made relentless progress on the outside to strike by a length.
Hillstar won by a length to provide trainer Sir Michael Stoute with a second Royal Ascot winner of the week.
Mutashaded finished third, another two and a quarter lengths adrift of the winner.
Moore said: "He was always a horse we liked and won a nice maiden last year.
"Both of his starts this year have been on really fast ground and the races didn't work out for him.
"The trip suited him. I was taken a bit further back than I would have liked, but he has a good attitude."
Stoute said: "We had him in the Derby and we had him in the Irish Derby, but his first two runs this year just haven't gone right.
"At Newbury last time the horse we thought would be the pacemaker was withdrawn and he hit the gate too well and was too keen.
"We dropped him out today and made sure he didn't do that,but we've always loved this horse."
Aidan O'Brien was not too disappointed with the performance of Battle Of Marengo.
He said: "He ran very well. He went an even pace and he was lobbing along there, but the other one came from the back to get him."
Asked about the possibility of the three-year-old dropping to a mile and a quarter, he said: "Possibly".
Mutashaded's trainer Roger Varian, said: "I was pleased with him, because he'd only had two previous starts and one this year.
"Paul (Hanagan) said they went a man's gallop and he was babyish, but he came through really nicely.
"He wasn't disgraced. We'll take him home and see how he is, as he's had a hard race."