It was a second Royal Ascot success for AMO Racing following Valiant Force's shock victory in the Norfolk Stakes.
The lightly-raced three-year-old was returning from a sizeable absence when runner-up on his stable debut in the Epsom Derby earlier this month and he showed no signs of the quick turnaround being an issue when strolling to Group 2 success this afternoon.
Confirmed front-runner Dubai Mile kept things simple out in front but he began to feel the pinch as the bell rang turning for home and the eye was always drawn to King Of Steel.
Kevin Stott peeled his mount widest of all as the field entered the straight and the Wootton Bassett colt displayed a potent turn of foot to take up the running inside the final couple of furlongs.
The 11/10 market leader stayed on strongly despite drifting to the rail and finished comfortable three-and-a-half lengths clear of Continuous (9/1) at the line.
Ralph Beckett's Artistic Star (15/2) was a further two-and-a-half lengths back in third.
Roger Varian said: "It is a relief! When they run so big in the Derby, you want them to back it up. We were confident King Of Steel would, but this is horseracing!
"We went on the signs that the horse was giving us. Raul Da Silva has done a wonderful job riding this horse most mornings, as has the whole team at home.
"I am delighted for Kia [Joorabchian], and was delighted that Kia got his winner yesterday, it took a bit of the pressure off us!
"I am delighted for the horse – he is a beautiful horse and, for a big horse, he is so agile. He confirmed today what he did in the Derby, which is very satisfying."
When questioned whether the Grand Prix de Paris will be the horse's next target, Varian said: "Possibly, that is what we'd like to do, but a lot can change with horses so let's see how he is tomorrow."
Joorabchian said: "I could hardly watch the whole way round, but when I heard the shouting in my box I knew we had hit the front. I was staying quiet until it happened.
"I love this track so much. I loved it as a kid and I wanted to run here, even though I know it was a big decision not to go for the Irish Derby. We decided to run here and then go for the Grand Prix de Paris after that.
"Alex Elliott [bloodstock agent] and I saw this horse [as a yearling] at Keeneland and Alex said 'if there's one horse I need you to buy, it is this guy'.
He was so big, twice the size of other yearlings. Alex and I started this [Amo Racing] together a long time ago and it was significant that we won this race.
"This horse floats – he's obviously got size and he's proven he can go on any ground. His first race, his maiden, was on soft and his last two races have been on firm so he's so diverse. He's going to be a wonderful horse."
Stott said: "I was nervous, I'm not going to lie to you. There was a bit of pressure and, after finishing second in the Derby, you have to go out and prove it was no fluke. He's a very good horse.
"We didn't go very fast and he was a bit keen. I couldn't really get him to drop the bit until halfway and I was a little nervous at that point thinking he might have been too keen, but in a matter of strides we were in front and he was just lengthening.
He could easily go back to ten furlongs because he has plenty of speed, and he's so quick on his feet for such a big horse.
"He has a blue eye on one side and you have to be nice and relaxed with him because he might be a tiny bit blind on that side.
You can see how big he is and, if he stays in training next year and fills into this big frame, you don't know how good he could be. It's very exciting for me and for Kia to have such a good horse."
Paddy Power immediately shortened the AMO Racing-owned colt to 6/1 from 10/1 for the King George VI next month.
