The Henrietta Knight-trained Best Mate romped home in the Cheltenham Gold Cup this afternoon to become the first back-to-back winner since L'Escargot in the early 70s.
The 13/8 favourite took command at the top of the hill and powered home to leave second placed Truckers Tavern (33/1) trailing 10 lengths in his wake. The Noel Meade-trained Harbour Pilot (40/1) was the leading Irish finisher in third.
At the start of the race, Behrajan and 1999 winner See More Business settled down at the head of affairs, setting a good pace.
Leading Irish hope Beef Or Salmon took a crashing fall at the third fence but he and jockey Timmy Murphy were quickly on their feet.
Best Mate was held up in mid-division as the field went out into the country for the final time and Behrajan went on.
Behrajan stayed in front until the winner's stablemate Chives was sent on by Richard Guest at the top of the hill, but Culloty had the move covered and joined the leader three out before settling the issue in a matter of strides.
As Chives faded out of contention it was Valley Henry who kept on to claim fourth place.
Winning jockey Jim Culloty said: "He [Best Mate] didn't settle as well as he normally does early on. It was atough race this year."
Best Mate's owner Jim Lewis said: "This is my moment, my once in a lifetime, and it doesn't get better than this. History has been made and I can't believe it."
Earlier, Baracouda denied Ireland's top challenger Limestone Lad to claim the Bonusprint Stayers' Hurdle.
The French-trained star led approaching the final flight and held the grey Iris's Gift, whose persistent challenge faltered as Baracouda became the first horse to score back-to-back victories in the three-mile championship since Galmoy in 1987 and 1988.
Limestone Lad was a heavy banker for Irish punters and started as 9/4 joint favourite with Baracouda, but hadto settle for third place after trying to make all.
In the opening race Barry Geraghty rode his fourth winner of the Festival when landing a dramatic race for the JCB Triumph Hurdle on Spectroscope.
The Jonjo O'Neill-trained four-year-old, a 20-1 shot, got the better of a protracted duel with Martin Pipe's Well Chief (7-1), ridden by Tony McCoy, who had set out to make all the running.
He prevailed by a head with 11-2 favourite Golden Cross five lengths back in third.
There was drama at the flight at the top of the hill where Old California, who was in second place, came down. He fired Rodi Greene into the ground and broughtdown three rivals.
Kingscliff maintained his unbeaten record with a stout staying performance in the Christie's Foxhunter Chase.
Held up in touch by Richard Young, the 11-4 favourite took closer order at the top of the hill before going on after four out, where leader Sheltering blundered away his chance.
The winner kept up to his work as his stride began to shorten up the hill, but the line arrived in time for him to land the spoils for trainer Sally Alner.
Kingscliff held on by two-and-a-half lengths from Bright Approach (20-1) with last year's winner last Option half a length back in third.
Henry Daly registered his second winner of the meeting when Palarshan took the Grand Annual Challenge Cup (Handicap Chase).
La Landiere maintained her fantastic winning run with a resolute display in the Cathcart Challenge Cup in the hands of Richard Johnson.
Barry Geraghty clinched the Daily Telegraph Leading Rider award with his fifth winner of the meeting on Spirit Leader (10-1) in the closing Vincent O'Brien County Hurdle (Handicap).