The six-year-old jumped well throughout and a bold leap at the final fence before the home turn opened a gap.
Stable companion Valseur Lido gave chase in the straight, but Ruby Walsh's mount won commandingly by 12 lengths.
Meanwhile, Al Ferof, a candidate for the King George on Boxing Day, won at Huntingdon by two-and-a-half lengths.
It was a successful debut for Nick Skelton in the Peterborough Chase at the Cambridgeshire track.
Last year's winner Wishfull Thinking set off at a rapid pace under Richard Johnson and put in some spectacular leaps, but Al Ferof and Ptit Zig cruised past the leader, whose run had come to an end with three furlongs to run.
When Ptit Zig took a tired fall at the last, Al Ferof was well on top and the 9-4 chance came home a long way clear of Pepite Rose.
Willie Mullins-trained Djakadam was the 7-4 favourite at Punchestown and, after briefly tracking 2012 winner Flemenstar, he was soon in control.
"Henrietta Knight said he will win the Gold Cup, so I'll quote her," Mullins said.
"I wasn't happy with him during the week and was nearly not going to run, but to run like that after the way he was, I'm absolutely delighted with him."
Last season's Cheltenham Gold Cup runner-up Djakadam sealed an impressive win in the two-and-a-half-mile Grade One John Durkan Memorial Chase.