Cole Harden made every yard of the running to win the Ladbrokes World Hurdle at Cheltenham for Warren Greatrex and Gavin Sheehan.
Allowed an easy time of things at the head of affairs, the six-year-old looked a sitting duck as all the market leaders stacked up behind him.
However, having had a breathing operation after his last run, Sheehan had saved plenty for the famous hill and a good leap at the last kept him three lengths clear.
Paul Nicholls' Saphir Du Rheu gave chase but he was three and a quarter lengths down at the line, with his stablemate Zarkandar the same distance back in third after a jolting mistake at the second-last cost him any chance of victory.
It was a first Festival success for trainer and jockey, coming at 16-1.
Greatrex said: "We've just won a Grade One and beat the best, so we're here, aren't we?"
Greatrex added: "If you're going to break your duck (at Cheltenham), you may as well do it in a big one.
"This means everything. I was struggling with him early season, but then he went and won at Wetherby and I didn't know what to think.
"I knew there was something wrong in the winter so we had his wind done after the Cleeve and I haven't missed a day since then.
"I need to thank my head lad Graham who does everything with this horse.
"We knew he was spot on, you don't come thinking you are going to win, but I knew the rest would have to be right on their game.
"I thought going to the last we had them as he wouldn't stop.
"It's fantastic. We're trying to compete with the big yards and hopefully this will help."
Sheehan said: "It's pretty special - very, very special.
"Warren got me psyched up before the race. With fractions, you can't get them right all the time but you can only feel what your horse is giving and he gave me an exceptional ride. His jumping was brilliant. He was very quick and did everything right.
"I was very nervous coming down the hill, I was holding on to him and wondering if I should send him on. Then I turned into the straight and he kept picking up and I was like 'where is everybody' but when I saw the line, it meant everything."
Of his placed runners, Nicholls said: "Zarkandar was travelling really well but he lost any chance when he made a mistake and I think he is dead unlucky.
"Saphir Du Rheu travelled extremely well but you can see why he's a chaser as he just lacks a gear on that ground."
Rebecca Curtis was more than satisfied with At Fishers Cross' effort in fourth under Tony McCoy.
She said: "He has run a blinder and it's nice to see him finish his race today. I think he bumped into trouble a couple of times and AP said if he knew he was going to finish like that, he would have had him a bit handier.
"It's nice to see him back to his best. The blinkers have done him no harm and and there's no reason why he won't go to Aintree as long as he's fine next week.
"The ground was probably quick enough for him today."
