We thought it was all about Kauto Star and Denman. But Imperial Commander completely turned the tables today at the Cheltenham Festival, winning the Cheltenham Gold Cup by seven lengths. Denman was second under AP McCoy, while Kauto Star, winner of this race in 2007 and 2009 and the 8-11 favourite, fell four fences from home.

Trained locally by Nigel Twiston-Davies, Imperial Commander put up the performance of his life under Paddy Brennan. He jumped economically and galloped strongly, passing Denman at the second-last and pulling away from him up the hill to the finish.

“This is by far the best day of my life,” said Brennan. “I’ll never forget this.”

It was a first Gold Cup for both jockey and trainer — although Twiston-Davies has two Grand Nationals to his credit, having won with Bindaree and Earth Summit.

Kauto Star made a bad mistake at a fence on the first circuit, but jumped extravagantly — despite having to be niggled once or twice by Ruby Walsh — until he got it all wrong at the fourth-last and crashed out. He was unhurt, and Ruby Walsh remounted and walked him home, but his jockey’s and trainer’s hopes of proving him the best steeplechaser of the past 40 years were dashed.

Considering Denman’s chequered history since his 2008 Gold Cup win — a serious heart problem, a fall at Aintree last spring and the recent ditching of AP McCoy at Newbury — he ran a cracking race. He just lacks finishing speed; his wins have been ground out by dominating from the front.

Imperial Commander, a nine-year-old by Flemensfirth, won the Ryanair Chaser at Cheltenham last year, then nearly beat Kauto Star at Haydock last autumn. But he couldn’t get close to the Paul Nicholls-trained champion in the King George VI Chase on Boxing Day, and there was a doubt about whether his stamina would last the 3m 21/2 furlongs round Cheltenham’s Gold Cup course. The doubters were wrong. Steeplechasing has a new king.

Mon Mome, the 100-1 winner of last year’s Grand National, sprung another surprise by finishing third at 50-1 for Venetia Williams and Aidan Coleman, while the popular Carruthers, Lord Oaksey’s game front-runner, was fourth under Mattie Batchelor.

Remarkably, Nigel Twiston-Davies’ day then got even better when he trained the winner of the Christie’s Foxhunter, Baby Run — ridden by his son Sam.