The 12-1 chance Al Boum Photo, ridden by Paul Townend, put in a superb display to give trainer Willie Mullins a first Cheltenham Gold Cup victory.
Mullins, the Festival's most successful trainer, had previously finished second six times in the prestigious race.
Al Boum Photo had some anxious moments with his jumping. but raced away to win by two-and-a-half lengths.
Fellow Irish challenger Anibale Fly (22-1) was second with the grey Bristol De Mai (18-1) back in third.
More to follow.
