Kauto Star created history with a fifth King George VI Chase victory in a perfect performance at Kempton Park.
The ever-popular 11-year-old, ridden by Ruby Walsh, won the race on four successive occasions from 2006 before being beaten by Long Run last season.
But the two-time Cheltenham Gold Cup champion gained revenge on this year's Gold Cup winner in spectacular style.
The 3-1 chance jumped superbly to finish a length and a quarter ahead of the evens favourite Long Run.
The victory is a remarkable turn of affairs for the Paul Nicholls-trained horse, whose career looked in doubt at the start of the season following the defeats by Long Run in the King George and the Gold Cup before pulling up at Punchestown in May.
There were many who believed that his Nicky Henderson-trained rival would progress from the Haydock defeat but his second loss in a row mean his odds to retain his Gold Cup title in March have been eased to 3-1 while Kauto Star is now around 9-2 to win the race for a third time.
Nicholls said: "He's just awesome and I knew we had him in serious order. I don't know why he wasn't quite right last year.
"It was a massive plus having Ruby here today and it's just unbelievable. It's amazing. He's just the best.
"If he gets to Cheltenham in that form he'll be the one to beat [in the Gold Cup]."
Kauto Star was never far away from the front of the field, as he had been when he beat Long Run to win the Betfair Chase at Haydock in November and led with a circuit to go.
He quickened the pace heading down the back straight and his jumping kept him at the head of affairs as Long Run had some less than comfortable moments with his jumping under Sam Waley-Cohen.
Although Long Run stayed on strongly in the home straight, he was unable to catch up on the winner.
Walsh said of Kauto Star: "He's an amazing horse. He looked a million dollars and he felt great. He jumped super and travelled great. This is a fairytale. He's a wonderful horse and it's a credit to the people who work with him every day.
"He's beaten a six-year-old [Long Run] and he's 12 next week. To keep a horse going as long as that is amazing.
"You can say what you want about the best steeplechasers of all time, but he's outlasted them all. He's lasted longer than any other horse and that's what makes him so brilliant.
"This horse is as tough as nails and he's exceptional."
The only downside for Nicholls and owner Clive Smith was the injury suffered by their other representative Master Minded who pulled up injured.
Earlier, the 2010 Champion Hurdle winner Binocular had to dig deep under Tony McCoy to win the Christmas Hurdle.
The 5-4 favourite had gone clear a long way from home with Rock On Ruby and Overturn and the trio jumped the second-last together before Overturn faded approaching the last.
Binocular, who had looked less than comfortable throughout the race, jumped the last better than Rock On Ruby and, although Rock On Ruby, ridden by Walsh, challenged strongly, McCoy was able to keep his mount ahead.