Penhill cut through the pack like a knife through butter to land the Albert Bartlett Novices’ Hurdle and give Willie Mullins his sixth winner at this year’s festival.
The 6yo, owned by Brighton & Hove Albion Chairman Tony Bloom, was given a wonderfully patient ride and was hampered by the fall of The Worlds End. However, he cruised into contention from the home turn before slicing through his rivals and scooting clear to defy his 16-1 odds.
The three-and-a-half length success also provided jockey Paul Townend with a quickfire 356-1 double after riding Arctic Fire to victory in the County Hurdle 35 minutes earlier.
Well-backed favourite Death Duty was in trouble by the home turn and was well beaten off when departing at the final flight.
Owner Tony Bloom said: "I'm over the moon for everyone involved, it was a great ride by Paul and it's a brilliant horse we have here.
"He was looking good all the way and two out we were expecting him to win, his hurdling was a lot better than it has been and he's got the pace. Racing over three miles has been the making of him, as it gives him more time for his jumping.
"I haven't had many Cheltenham runners, so it is very exciting. I've brought a lot of friends and they're all on at 16 and 20/1."