Nicky Henderson's charge won a thrilling renewal of the most prestigious of all National Hunt events under Barry Geraghty.
It was a 50th Festival win for trainer Henderson as the 11/4 favourite came home by seven lengths from Sir Des Champs (4/1) with 2011 champion Long Run (7/2) in third.
Bobs Worth looked out of it at the top of hill after being impeded by Silviniaco Conti but recovered and powered up the hill at the end of the 3 mile, 2½ furlong contest to add his name to the roll of honour features the names of such chasers as Arkle, Best Mate, Golden Miller, Kauto Star and Mill House.
The eight-year-old was the winner of the RSA Chase last season and successful in the Albert Bartlett 12 months earlier and was well backed for a Festival hat-trick.
The winning jockey said: "He has a great attitude and travelled, although he was struggling on the ground.
"I was hunting them and turning in I thought I had every chance and thought I should win. He's game as a lion and loves the job."
Champion jockey Tony McCoy won the race in 2012 on Synchronised and came close after replaced the injured Davy Russell on Sir Des Champs but Willie Mullins' entrant was outstayed up the hill as the winner shrugged off concerns about the soft going.
Henderson also saddled the third as the Waley-Cohen's former winner Long Run made a game bid to regain his crown. The eight-year-old was a long-time leader but eventually finished two and three quarters length back.
Henderson said: "They were great - both horses were fantastic. Everyone has done one hell of a job as we've purposely not run them.
"Bobs Worth has not run since the Hennessy and Long Run since the King George and it's all down to what they've done at home and what the team have done, so credit to them all."
Our Conor could be a star in the marking after routing the opposition to win the Triumph Hurdle.
It had been more than 10 years since there was an Irish-trained winner in the leading event in the National Hunt calendar exclusively contested by juveniles but Our Conor (4/1) ended that barren run with a 15 length victory.
Dessie Hughes' charge was unbeaten in three starts before today and took over the lead from pacesetter Diakali on the long run-in to the final flight and showed a devastating turn of foot under jockey Bryan Cooper.
Winners of the Triumph Hurdle often go on to compete in subsequent editions of the Champion Hurdle. Four horses have achieved victory in both events – Clair Soleil, Persian War, Kribensis and Katchit - and the horse earned a quote of 8/1 for next year's renewal.
"I was trying to sit for as long as I could," said the rider, who won Thursday's Jewson on Benefficient.
"He has got some ability, he has got such a good cruising speed and he has everything you need. I was happy the rain came and I couldn't ask for anymore. I couldn't be happier for the boss."
It was also Ireland's 11th victory of the Cheltenham Festival with Far West (4/1) a distant second ahead of outsider Sametegal (33/1).
Nicky Henderson won this two seasons ago with Soldatino on the back of one run in the UK but heavily backed favourite Rolling Star (5/2) faded badly after looking poised to strike two out.
County Handicap Hurdle
Bryan Cooper completed a memorable double on Gold CUp day as Ted Veale got up to win the Vincent O'Brien County Handicap Hurdle.
Tennis Cap looked to make all in the Grade 3 affair but 20-year-old Cooper - the son of Tom Cooper, the trainer of Cheltenham Festival winners Total Enjoyment and Forpadydeplasterer - produced a patient ride and went to the front going over the last.
One and a half lengths was the winning margin for Tony Martin's 10/1 shot to make it 12 wins for Ireland at the Festival.
Martin said: "I was lucky to have [Ruby] Walsh and [Paul] Carberry working for me in the past but this lad is an able deputy.
"The ground was against us at Leopardstown last time but fortunately it's worked out for us today."
Willie Mullins was denied the chance to saddled the winner of this race for the third time in four years but Tennis Cap made it a 1-2 for Ireland, finishing four and a half lengths ahead of Manyriverstocross (25/1) with Shadow Catcher (16/1) fourth.
Albert Bartlett Novices’ Hurdle
There was a first winner of the 2013 Cheltenham Festival for champion jockey Tony McCoy as 11/8 favourite At Fishers Cross won the Albert Bartlett Novices' Hurdle
Rebecca Curtis' charge was the subject of big support after his form was franked by outstaying Wednesday's impressive Neptune Investment Management Novices' Hurdle winner The New One here in January.
After O'faolains Boy led for most of the three-mile slog, African Gold and At Fishers Cross made their move down the hill and the favourite had edged into the lead going over the last.
And JP McManus' six-year-old powered up the hill to win by four and a half lengths to become the third winning favourite since the race was incepted in 2005.
Nigel Twiston-Davies is having a good Festival and African Gold (9/2) held on for second by a neck from Inish Island with Ruby Walsh on board.
The Foxhunter Chase, the 'amateur Gold Cup', provided the most dramatic finish of the Festival as Oscar Delta unseated his rider on the flat after the last fence when looking the likely winner.
That allowed 2/1 favourite Salsify to retain the title and left Oscar Delta's teenage jockey Jane Mangan in tears after that amazing finish.
Rodger Sweeney's charge stays forever but was three lengths back as the leader drifted left and unshipped the inexperienced amateur with victory in sight.
Divine Intavention (50/1) was 20 lengths back in second with 9/1 shot Cottage Oak third.
Martin Pipe Conditonal Jockeys
Paul Nicholls finally got a winner at the 2013 Festival courtesy of his 17-year-old nephew Harry Derham who guided Salubrious to the Martin Pipe Conditional Jockeys' Handicap Hurdle.
After 25 misses the leading National Hunt trainer of his generation landed with the 16/1 shot who defeated 33/1 chance Nagpur by seven lengths.
Pacesetter Double Ross (14/1) was a length further back in third ahead of Make Your Mark (8/1).
It was a first win at the Festival for Derham who said: "It has been a tough week. It is so competitive here at the festival.
"We talked about the race before and thought we'd take our time with him and ride him to run through horses and it suited him well."
Johnny Henderson Grand Annual Chase Challenge Cup
Tony McCoy and JP McManus completed a double on Gold Cup day as favourite Alderwood won the Johnny Henderson Grand Annual Chase Challenge Cup.
Three and a half lengths was the victory margin for the 3/1 market leader, who was a Grade 1 winner over hurdles last season, in the oldest chase in the present National Hunt calendar.
Kid Cassidy (12/1) followed with 10 lengths back to former winner Oiseau de Nuit (33/1) and Drumshambo (20/1) completed the places.