AP McCoy last night revealed his reasons for choosing Double Seven ahead of Colbert Station in tomorrow's Grand National at Aintree.
McCoy, who won the big race for the first and only time in 2010 on Don't Push It, feels Double Seven is an improving horse.
Both horses belong to JP McManus, also the owner of Don't Push It.
Ulsterman McCoy, who will be crowned champion jockey for an unprecedented 19th successive time later this month, said: "Double Seven has run some decent races this season.
"He is improving, although this is a step up in class for him.
"Colbert Station has been a little bit out of form."
And McCoy, who made a couple of bad calls at last month's Cheltenham Festival, admitted: "Sometimes you pick the wrong horse!"
McManus' other possible, Lost Glory, was the only horse – who was guaranteed a run – to be taken out at the 48-hour stage of the first ever £1million Grand National, the prize boost courtesy of new sponsors Crabbie's.
County Kildare trainer Peter Maher feels he has Ulster-owned Big Shu in the shape of his life ahead of the Grand National – which is already a 70,000 sell-out.
Big Shu won the Cross-Country Chase at the Cheltenham Festival 12 months ago and finished third in the race last month, beaten three lengths by Balthazar King, who also runs at Aintree.
With Ulster Grand National-winning jockey Paul Carberry taking the mount on Monbeg Dude in the world's greatest steeplechase, Maher was on the lookout for a jockey and surprised a few when booking Ulsterman Peter Buchanan, stable jockey to Lucinda Russell in Scotland.
"My nerves are in bits!" said Maher.
"He deserves a crack at this, people have said I should have saved him for the banks race at Punchestown, but you only get one real crack at the National.
"He's the sort of horse you can only train properly for one race each season and this year we decided on the National. He's in the best shape of his life.
"Peter Buchanan came over on Saturday to pop him over a few National-style fences, I wanted him to have a feel of him.
"I thought very hard about who would ride him and I came in for a bit of stick in Ireland for overlooking some of the lads based at home.
"Peter is a true horseman, he's competed in show jumping for Ireland and I know he'll look after the horse for me," said Maher.
"One thing he does need is rain, though – they can go flat out early on and if it rains that might just slow him down early on."
Tidal Bay and Long Run head a maximum field of 40 after the leading fancies stood their ground at the final declaration stage.
The teenage Tidal Bay will carry top-weight of 11st 10lb in the hands of Sam Twiston-Davies, with Cheltenham Gold Cup and dual King George VI Chase hero Long Run next in on 11st 9lb under Sam Waley-Cohen.
Long Run's trainer Nicky Henderson also has Hennessy Gold Cup winner Triolo D'Alene, Hunt Ball and Shakalakaboomboom in contention as he aims to secure his first victory in the race.
Last year's third Teaforthree heads the market for Welsh trainer Rebecca Curtis, with Nick Scholfield the man on board.
Other leading contenders include Michael Scudamore's Monbeg Dude, the Willie Mullins-trained Prince De Beauchene and Rocky Creek from the Paul Nicholls yard.
The 40th and final horse in the field is the David Pipe-trained Swing Bill, although there are four reserves.
Goonyella, Soll, Night In Milan and Minella For Value could potentially get a run if there are withdrawals from the final 40.