Second to Well Refreshed in the race 12 months ago, Rigadin De Beauchene pulled up on his final two starts last season and was having his first run of this campaign, which went some way to explaining his starting price of 16-1.
Emperor's Choice (11-2) had won the West Wales National in a real slog only two weeks ago so deserved plenty of plaudits for running such a game race, but, in truth, the 10-length winning margin could have been doubled.
Red Rocco deserves a mention as he was still in contention after leading when they turned into the straight and he looked booked for second until he unseated at the last. The well-fancied pair of Merry King and Our Father were ultimately disappointing.
Robbie Dunne is no longer attached to Williams' yard but retained the ride at the wish of Rigadin De Beauchene's owner after the partnership won Warwick's Classic Chase last season.
Williams said: "This race was one we'd always aimed at with him. He had a problem in November time when he was coughing a bit.
"We had hoped to get him to Warwick for the race he won last year, but we decided to leave off as we were rushing him. We've nothing else in mind for him for now. The race for him would be the Scottish National if it came up soft."
Owner Andrew Wiles said: "He's a half-brother to Miko De Beauchene who won this for me in 2008 and with him being second last year this is one of my favourite races. I was keen for Robbie to ride him as he gets on very well with him."
Conor Ring was given a 10-day ban (March 1-10) for continuing on Wychwoods Brook when his mount appeared exhausted and eventually fell.
A good day for Williams was made even better when the mare Toubeera (5-1) beat the boys in the Grade Two Albert Bartlett Novices' Hurdle. Kaki De La Pree went with her over the last few flights but the concession of 10lb proved too much and Toubeera pulled away to win by 12 lengths.
The fairytale story of Seeyouatmidnight (6-1) continued apace as Berwickshire trainer Sandy Thomson's promising youngster made all of the running in the Betfred Mobile (Rendlesham) Hurdle.
Thrown in at the deep end against last year's World Hurdle runner-up Celestial Halo, Ryan Mania was keen to make it a real test as, one by one, his rivals dropped away.
Only the mare Mickie was still in contention at the last but Mania kept him up to his work to win by a length and a quarter. "It's unbelievable. All of racing wants a horse of their dreams and we've got one," Thomson said. "Of course I'm surprised, he's done things I never expected.
"He was impressive at Hexham and I knew he was decent as he wasn't wound up, but I didn't think he'd do that in this company.
"He's a chaser in the making so we didn't enter him at Cheltenham and he'll go to Aintree back against novices, I'd imagine."