Big Buck's was the undisputed No.1 in the three-mile division with four Ladbrokes World Hurdles among a string of 18 successive victories from January 2009 to December 2012, until injury intervened and he was unable to defend his title last year.
Although beaten on his comeback run in the Cleeve Hurdle in January, the Paul Nicholls-trained gelding went down with all guns blazing in third behind Knockara Beau.
Everything has gone to plan since then, and Stewart is looking forward to facing the Willie Mullins-trained Annie Power, who has replaced Big Buck's as favourite and takes a 100% record into the race.
Stewart said: "We massively respect the mare. She's unbeaten, but there are question marks over whether she will stay and if Big Buck's is back to his top form is she good enough? We think Big Buck's is back to his top form, but, just like his owner, he's getting on in age. He's done nothing wrong at all with his preparation since he was beaten three-quarters of a length in the Cleeve. If he had won by that margin, he would not be 3-1.
"I spoke to Sir Alex Ferguson and he said if a player had been off for 42 days he would start him off in the reserves and not play him for the full 90 minutes until he'd had three or four games. With Big Buck's there was nothing else you could do but put him in a competitive race over three miles giving a bit of weight [8lb] to the winner [Knockara Beau], and he'd been off for 420 days plus it only the second time he'd been on turf.
While delighted with Big Buck's, Nicholls admits he cannot sure if he is as good as he was. "He'll love the ground, but he's 11 now and, as we saw with Hurricane Fly in the Champion Hurdle, can they be what they were?"
Sam Twiston-Davies rode Big Buck's for the first time in the Cleeve and is confident of a big run. "He must go there with a great chance. He's improved to suggest he could win a fifth."
Stewart's colours will also be carried by Celestial Halo, who was an admirable deputy for Big Buck's 12 months ago when second to Solwhit. He is also represented by Salubrious, who is owned jointly by the Johnson and Stewart families.
Nicholls is mob-handed as he has a fourth runner in Zarkandar. "It is just that we have no middle-distance hurdle race - 2½ miles - like they have at Aintree," said the Ditcheat handler. "But there will be a good gallop whatever happens; it certainly won't be lacking in pace, that's for sure."
Annie Power is undoubtedly the one with untapped potential and connections have every faith in her as she steps up in distance and class. "Everything is fine, she's travelled over well," said Mullins. "She's running over three miles for the first time. We're hoping she'll stay. I don't expect her to have any problem with the drying conditions."
If anyone knows of potential weak links in Big Buck's armour then it is Annie Power's jockey Ruby Walsh, who rode the Nicholls horse to his four World Hurdle triumphs.
He said of Annie Power: "She's a very good mare. She has lots of potential, she has pace and oodles of stamina and we haven't got to the bottom of her. Her form is solid, she's beaten Zarkandar twice in England this year and then won over two miles at Doncaster. Fingers crossed the real Annie Power will show up."
At the start of the season, At Fishers Cross was the one widely tipped to succeed Big Buck's as the champion after his victory in the Albert Bartlett last March. He disappointed in the first half of the campaign, but did have valid reasons for performing below par and showed he was on the way back when finishing ahead of Big Buck's when a close second to Knockara Beau in the Cleeve.
His rider, Tony McCoy, is optimistic of a good run. "I felt At Fishers Cross was much more like his old self at Cheltenham on Trials Day, and while he needs to step up again things are going the right way," said the champion jockey.
McCoy chose At Fishers Cross over owner JP McManus's other runner, More Of That. Though he is untested over this distance, his trainer Jonjo O'Neill believes his stamina will last out and he has won all his four starts to date.
Reve De Sivola is one of the outsiders this year after being sent off the 4-1 second favourite 12 months ago when he was fourth to Solwhit. Paul Duffy, who heads the Diamond Partnership syndicate that own the nine-year-old, feels he is the forgotten horse in the line-up.
He has been a leading stayer for some time, lifting the Long Walk Hurdle at Ascot for the last two years and winning a massive pot at Auteuil in November. "He's well enough and we take our chance. He's a bit of a forgotten horse. Going up the hill, he'll be running on and doing his best," said Duffy. "He does go through good ground, it's just how it relates to the other horses. We are certainly hopeful for a place."
His trainer Nick Williams believes Reve De Sivola is over-priced and could be good value this time. "The race at Ascot [Long Walk] to the World Hurdle was probably too long a gap. I felt the Rendlesham was too close to Cheltenham and there weren't that many options," he said. "I regard Reve De Sivola as a very good, solid each-way prospect. He was 4-1 last year, he's about 20-1 this year. To me he's good value."
Mala Beach was a good winner of the Grade Two Galmoy Hurdle at Gowran in January and his trainer Gordon Elliott sees the six-year-old as a horse for the future. "Mala Beach is an out-and-out galloper really, a big staying chaser in the making," said the County Meath handler. We said at the start of the year we'd mind him for next year which is what we've done. Every horse in the race has niggly doubts; I suppose Annie Power is the one everyone is afraid of."