Martyn Meade's colt was the 11-10 favourite in the hands of Frankie Dettori, with three of his four rivals trained by Aidan O'Brien, who had saddled a staggering 16 winners of the race in the last 20 years.
Advertise had finished marginally ahead of the reopposing Sergei Prokofiev when they came home second and third in the Coventry Stakes at Royal Ascot in June, since which Meade's charge had claimed an impressive victory in the July Stakes at Newmarket.
The Irish Rover adopted a pacesetting role, with Advertise always in his slipstream.
With Sergei Prokofiev failing to fire, The Irish Rover and Advertise settled down to fight it out and were joined by So Perfect racing inside the last of six furlongs.
There was little to split the trio as they raced for the line, but Advertise stuck his neck out to score by half a length, with So Perfect beating The Irish Rover to the runner-up spot.
Advertise is the first British raider to claim the Phoenix Stakes since Mark Johnston's Princely Heir in 1997.
Meade said: "I've been quite bullish about this horse and luckily it's paid off, otherwise I might have had to eat my words a bit.
"I'm very pleased with him, it's great, and maybe we'll step him up to seven furlongs now.
"We'll give him a bit of a break and then go for the Dewhurst or something like that I suppose. It seems logical and he'll get further."
He added: "The big question is if he'll get a mile, but he'll definitely get seven.
"It was a great result. Obviously I was coming here with a lot of trepidation, but you can tell very good horses at home, going to perform for you, got the form and did the job.
"If you've got a good horse it makes a difference, you don't have to struggle too much then.
"It was a great ride by Frankie and it's great to have him on board. As he said to me after he won the July Stakes, 'send him anywhere you like' and that proved to be right.
"I'm thrilled to bits with him. Every run he's been held up and produced with a turn of foot, but he was able to dictate today and it shows that he knows his job now."
