Al Boum Photo gave trainer Willie Mullins his first victory in the Cheltenham Gold Cup following a dramatic race for the showpiece event at the Prestbury Park course.
Leading at the second-last fence, Al Boum Photo (12-1) dug deep for jockey Paul Townend, who was also winning the Gold Cup for the first time.
Anibale Fly stayed on strongly to finish second, two and a half lengths away, with Bristol De Mai another three and three-quarter lengths back in third.
After six second places, Mullins finally broke his Gold Cup hoodoo. His three other runners - Kemboy, Bellshill and Invitation Only - failed to finish.
An emotional Townend said: "I can't believe it. It's the Gold Cup, there's only one a year and I never dreamed I'd win it.
"Like any race, when you're going well it's so simple. It's unbelievable and I'm privileged to be riding for Willie Mullins."

A typically understated Mullins said: "It feels great. I'm delighted for Paul and delighted for connections. It's good to get it.
"I was here when my dad (Paddy Mullins) won with Dawn Run and I didn't get home for two days.
"I sort of resigned myself to never winning a Gold Cup. Certain jockeys may never win the feature race of their lives, like the Grand National or the Champion Hurdle. I thought maybe I'm not going to be lucky."
There was a sad postscript for the winning team, however, as it later emerged the fall at the 10th fence of stablemate Invitation Only had proved to be a fatal one.