Edwardstone led relatively unpressed from the rest of the field in the early stages until El Fabiolo made a big mistake at the fifth and was soon pulled up by jockey Paul Townend.
Willie Mullins was expected to have a century of winners in this race as El Fabiolo went off as a 2/7 favourite.
It was an error at the fifth fence by the seven-year-old that saw El Fabiolo out of the race.
Edwardstone made much of the running before Captain Guinness began to make headway down the hill approaching the third last.
Captain Guinness travelled best throughout and held off a late challenge by Gentleman De Mee to give Rachael Blackmore another winner.
The Henry de Bromhead-trained Captain Guinness won at a price of 17/2.
“We felt we had a right chance when El Fabiolo came down,” said trainer de Bromhead speaking to ITV. “To get this race, is just incredible.”
Jockey Rachael Blackmore added: “He always run his race – he’s enthusiastic. His style of running is now a lot more reserved.”