Having finished second to Alcohol Free at Royal Ascot, with Guineas winner Mother Earth just behind in third that day, the trio dominated once again, with Lady Bowthorpe doing her best to gatecrash the party but getting going too late.
Alcohol Free attempted to make all against the far rail, with Mother Earth keeping close tabs on her.
Sean Levey would have had a few anxious moments wondering if he was going to get a run, as he was trapped behind horses just as the pace quickened and he gave Primo Bacio a nudge when beginning his run.
The grey really picked up, however, and flew home with an irresistible run, winning by half a length at 6-1.
Mother Earth was a neck in front of Alcohol Free, with the same back to Lady Bowthorpe, who had to come widest of all.
Snow Lantern trainer Richard Hannon has never made any secret of the regard in which he holds the filly, a daughter of Sky Lantern who won the 1000 Guineas for the yard.
Sky Lantern was later felt to be an unlucky loser in the 2013 renewal of this Group One, so Hannon will feel a sense of vindication - especially as this filly is a homebred out of Frankel.
Hannon said: "It's very special because of the whole Sky Lantern story. It's great for Rockcliffe Stud as they hadn't had a Group One winner until today.
"We went to York to try to bag one of those (stakes races) and it didn't work out, but she's learnt to settle since then.
"She was a little bit unlucky in the Coronation. She looked exceptional when she won her novice at Newbury and she looked exceptional there today, I think - she's a very special filly."
On plans, he said: "We'll sit down and have a think, but I do think she'll get a mile and a quarter.
"She's in the Nassau and the Sussex, so we'll look at Goodwood and I'd probably be leaning towards the fillies' race (Nassau).
"She's in the Juddmonte International as well, but I'm very hopeful she'll stay in training next year, so I'm happy to give her a nice time."
Levey said: "It's taken her a couple of steps to get to this point and it's thanks to everyone in the yard. They have done a massive job. She's not the easiest, so it's great for everyone it's all come to fruition now.
"She's known to be keen, so my hands were tied as far as tactically what I could do with her. She came out of the gates fairly relaxed. As soon as they came over to that rail I knew I had to hold position when I was trying to settle her. I did think it would be very hard to get out of there.
"Lucky enough I was able to switch her round just in time to pick them up."
He added: "It means a massive amount. I've had Billesdon Brook, who was great, and King Of Change as well, but a lot of work has gone into this filly. In the yard she comes with a huge thing because Sky Lantern was her mother.
"For everyone it's a big deal."