Bobs Worth justified favouritism to win the Cheltenham Gold Cup on Friday and give trainer Nicky Henderson his 50th career win at the Cheltenham Festival.

Ridden by Barry Geraghty he came home seven lengths clear of Irish challenger Sir Des Champs while 2011 champion, Long Run, also trained by Henderson, was third.

"It's dreams, isn't it? Barry Geraghty gave that a lovely pace," Henderson said.

For Geraghty it was an even greater triumph as he had bought the horse originally as a yearling for almost STG14,000 ($A20,000) and sold him to Henderson for STG21,000 as a four-year-old.

"It was brilliant. He is such a great little horse who just loves the job," said Geraghty, whose previous Gold Cup success came in 2005.

"We had faith in the horse. Nicky Henderson knew he would have him fit enough, he knows how to get them ready for Cheltenham."

Earlier 16-times champion jockey Tony McCoy finally broke his duck for the meeting, when he guided 11-8 favourite At Fishers Cross in The Novices Hurdle.

Both McCoy, and winning owner JP McManus, however, didn't feel like celebrating, preferring to talk about 37-year-old Irish amateur rider JT McNamara, who broke two vertebrae in his neck in a terrible fall on Thursday.

This time last year McNamara had been enjoying success on the McManus-owned and Curtis-trained Teaforthree at the Festival.

"It is very difficult to enjoy today after JT McNamara's injury. He is like a family member and it is very sad," McCoy said.

McCoy and McManus were to round off the meeting with a second winner, Alderwood, trained by Tom Mullins - brother of the meeting's leading trainer Willie - giving the Irish a record haul of 14 winners at the Festival.

Jockey Bryan Cooper had landed the first two races of the final day, taking the young rider to three for the meeting.

The 20-year-old Irishman won the first The Triumph Hurdle on the impressive Our Conor, who made light of the terrible conditions to canter home 15 lengths clear of the field.

Bookmakers immediately marked the Dessie Hughes-trained four-year-old as the horse most likely to dethrone Irish compatriot Hurricane Fly in next year's Champion Hurdle.

"This horse has got so much class, he's got everything," Cooper said.

"It's unbelievable. He could give Hurricane Fly a run for his money next season."

Cooper followed that win up with a patient ride on Ted Veale in the County Hurdle for his main employer in Ireland, Tony Martin.

The Irish wave of winners continued as Salsify, under a brilliantly-judged ride by amateur Colm Sweeney, retained his Foxhunters Chase title.

The race, though, will be remembered more for Jane Mangan being unceremoniously dumped on the ground when her mount and leader Oscar Delta swerved on the flat.

"I felt like I had the race won. This is a nightmare," she said.