There was a momentary worry that the 10/1 shot would fail to start as he entered the stalls, but Fallon managed to get him in place and a decent enough start.
He went on to win by a head from Lethal Force in a tight finish.
"Things went wrong for me. Drawn 18 I couldn't get too much cover and I got there too soon," said Fallon.
"He was going to walk straight in [to the stalls]. He was as good as gold but his shoulder hit the sidebar and spooked him. Other than that, he would have been fine.
"I didn't know if I had won. The other horse was bearing down on me and you never know."
7/1 shot Gordon Lord Byron was third with 7/2 favourite Maarek fifth.
James Fanshawe's six-year-old Society Rock was third last year as the race was reinstated.
Fanshawe said: "I always hold my breath when he's in the stalls because he lost his chance at Royal Ascot last year and it's half the battle with him.
"He's done a lot of work at home and he's going to be an exciting horse this season.
"He likes Ascot and [the Diamond Jubilee] will be his next race."
4/6 favourite Liber Nauticus won the Group 3 Tattersalls Musidora Stakes under Ryan Moore and could be in line for a run in the Oaks.
Ballymacoll Stud racing manager Peter Reynolds said: "It was a bit of a muddling race. It didn't really help her, but it was only her second race. She's a bit of a baby and she'll have learned a lot from today.
"[Owner] Sir Michael [Stoute] will make a decision about Epsom. Some people might say that because she is big and strong she might be more suited to the Curragh [Irish Oaks] but we'll let Michael make that decision."
- Sports & Recreation