Wearing the second colours of the late Trevor Hemmings, who won this race with Trabolgan, Many Clouds and Cloth Cap, the Venetia William-trained eight-year-old held the persistent challenge of Fiddlerontheroof in the hands of Charlie Deutsch.
Hemmings' first colours were carried by last year's winner Cloth Cap, who helped set the pace from the outset.
There were a few casualties with Enrilo falling at the 14th fence and Remastered coming down when in contention and going well at the fourth-last fence, while the Irish-trained favourite Eklat De Rire was pulled up by Rachael Blackmore after the sixth-last obstacle.
Cloudy Glen led three out but Fiddlerontheroof looked the main threat and the pair had the race between them. It was the former who kept up the gallop to score by half a length. The pair pulled 28 lengths clear of Brahma Bull in third with Ontheropes fourth.
Cloudy Glen was a product of Hemmings' Gleadhill House Stud, being a son of Cloudings who has provided many winners in the famous silks - not least Grand National hero Many Clouds.
Hemmings died last month at the age of 86 and Williams felt victory in this race was a fine tribute to the owner.
She said: "It was written in the stars. Trevor (Hemmings) was looking down. To have his two horses making the running in the Hennessy, turning for home. It is just unbelievable, isn't it?
"He was just wonderful as an owner. He had the most wonderful, wicked little sense of humour.
"But he understood horses. You had to be patient. In his business he was really on it, but with his horses, he was so patient and knew what it took.
"This fellow was winning off one of the bottom weights and he has had a wind operation since the last time he ran. We couldn't even do the galloping scope because he is such a quirky horse and he wouldn't let the vet get anywhere near with that scope. But he has always been a weird one and he did a piece of work last week and I thought 'blimey! Where did that come from?'.
"So, I decided then I was going to run him in this race.
"He will be out partying with us this evening, because he is that kind of horse!"