Inothewayurthinkin upstaged Galopin Des Champs in the Boodles Cheltenham Gold Cup on Friday to cap a sequence of surprise results at this year’s Festival.
Galopin Des Champs was expected to cement his place among the pantheon of great steeplechasers by winning chasing’s premier prize for the third successive year but, like so many hot favourites this week, the 8-13 market leader came up short.
The two-time winner did not look comfortable from an early stage, having been held up in the first half of the race, but when he led turning into the straight it seemed he would emulate such as Arkle and Best Mate by completing a hat-trick of triumphs.
However, he could not get away from the stalking Inothewayurthinkin, who surged clear under Mark Walsh after leading at the final fence to give trainer Gavin Cromwell the biggest success of his burgeoning career.
Gentlemansgame was a game third, with Monty's Star fourth. King George winner Banbridge did not jump with his usual fluency and trailed home last of the seven to complete.
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"I'm absolutely speechless," Comwell told Racing TV. "We've had a lot of faith in this horse. Credit has to go to Keith Donoghue with this horse, he's been a part of him all the way.
"He's done all the schooling and ridden him all the way along. I'm just thrilled. I was worried about the pace of the race on the better ground, he was only just hanging in there the whole time - he was flat out.
"He's a very good horse. Going down to the second last I thought we had a good chance, what can you say? It's brilliant, I'm just thrilled.
"Great thanks to JP and Noreen (McManus) for having the confidence to supplement him. It's brilliant, they're so good to train for. They're brilliant people."
Inothewayurthinkin was not originally entered for the Gold Cup in January but was supplemented at a cost of £25,000 last weekend by McManus.
Walsh tells Lydia Hislop more
The seven-year-old, who had finished behind Galopin Des Champs in his two previous races, vindicated the roll of the dice by sprinting clear to win by six lengths.
However, triumph was tainted by tragedy for McManus, whose other runner, Corbetts Cross, trained by Emmet Mullins, was fatally injured after a fall at the second-last.
A statement from the British Horseracing Authority read: "In our fifth race of the day, Corbetts Cross was immediately attended to by our veterinary professionals, but sadly sustained a fatal injury. Our heartfelt condolences are with his connections."
Front-running Ahoy Senor also fell seven from home, but was unscathed.
Inothewayurthinkin is also entered in the Randox
Grand National at Aintree next month and could now try and become only the second horse in history to win both races in the same year.
The only horse to have previously pulled off the double was Golden Miller in 1934. Inothewayurthinkin is no bigger than 3-1 to emulate him. He will run off a rating of 160 and will carry 11st 5lb as things stand.
Walsh was a sea of calmness moments after his biggest win but said: "I'm dancing inside! It's brilliant, I can't believe it.
"They went a nice gallop, he jumped well on the whole but just missed the ditch down the back there. I was always on the outside, early on he missed a few fences and I just saw Paul (Townend on Galopin Des Champs) wasn't happy, so I was happy to see that.
"Credit to this fella, he's had to do some growing up the last year. He won here last year, but Gavin Cromwell is a genius. He's a homebred as well, which makes it extra special."
Paul Townend said of Galopin Des Champs: "He tried his heart out and he's home in one piece. He'll go again.
"He was just not happy, everything was a bit of an effort. He still gave it a crack and gave them something to shout about for a long way.
"A couple of jumps back up to the top of the hill, I was hoping rather than feeling confident that he was going to come alive for me there, to be honest. He's run a blinder."
Watch what the vanquished had to say
Willie Mullins
Paul Townend
Mouse Morris
Henry de Bromhead
Joseph O'Brien