Long Run blocked Kauto Star's march into racing history as the young pretender denied his rival a record-breaking fifth victory in the King George VI Chase.It had been suggested since Boxing Day 2009 that Nicky Henderson's prodigy could be the most potent threat to Kauto Star when he made a staggering introduction to British racing on the very afternoon when the old master racked up four in a row in the King George.And at not much over half Kauto Star's age Long Run ushered in a new era under Sa

Long Run blocked Kauto Star's march into racing history as the young pretender denied his rival a record-breaking fifth victory in the King George VI Chase.

It had been suggested since Boxing Day 2009 that Nicky Henderson's prodigy could be the most potent threat to Kauto Star when he made a staggering introduction to British racing on the very afternoon when the old master racked up four in a row in the King George.

And at not much over half Kauto Star's age Long Run ushered in a new era under Sam Waley-Cohen, finishing 12 lengths clear of his stablemate Riverside Theatre with Tony McCoy and Kauto Star a further seven lengths third.

It was not the outcome so many who had made the pilgrimage to the outskirts of London had hoped for, with the statue of fellow King George legend Desert Orchid spruced up from its slightly dishevelled state in preparation of the rescheduled big day.

But trainer Paul Nicholls felt the champion and 4-7 favourite was already beaten before a terrible mistake at the second-last sealed his fate.

"Sometimes when you watch him, you know he's going to win but I never thought that today," Nicholls said.

"I was never really happy at any stage. The mistake cost him second but he has done incredibly well to even come here five times.

"He just looked like he had lost half a yard around here at the age of 11. He's come back safe and sound, that's the main thing."

Grade One wins for amateur riders are exceedingly rare and Waley-Cohen delivered the perfect reply to those who suggested Long Run needed a more experienced pilot.

He emphasised the need to get the 9-2 favourite to take on his fences with enthusiasm as he sat in behind Nacarat.

Long Run had parried the last of Nacarat's challenges turning for home and the greatest jumping prize outside Cheltenham and Aintree was his.

"This is the end of a long journey," Waley-Cohen said.

"He walked through the first but the thing we wanted to do was to get him to jump. It was a change of tactics to just go big and bold, and a couple of times I wasn't sure if I would get to the other side. But we had to take the sword to the king.

"I just wanted to get around the turn and then kick over the last three fences. It's just a special day."

Long Run is owned by Waley-Cohen's father Robert which made the victory even sweeter for the 28-year-old jockey.

"They are not just my hopes and dreams but for Dad and everyone else in my family.

"I desperately wanted to do well for them and it's a massive honour to be on a horse like this. Kauto Star is a fantastic champion and Tony McCoy is an idol for everyone in the weighing room. To be involved in a race like this is such a privilege."

Long Run's two British defeats have been at Cheltenham but connections strongly hinted that the Gold Cup, for which Long Run is the 9-2 second-favourite with sponsors totesport, could be on the agenda.

Kauto Star could have his opportunity for revenge at the Cheltenham festival.

"I'll sit down and have a talk with Clive (Smith, owner) but if he is sound and well there is no reason why he can't run in this year's Gold Cup," Nicholls said.