There proved to be no stopping Ruby Walsh for the third day in a row at the Cheltenham Festival today as he claimed his fifth victory of the week on Big Buck's in the Ladbrokes World Hurdle.

Walsh, who rode a treble yesterday, survived a mistake by the 6-1 chance at the last to hold off Barry Geraghty and Punchestowns by a length and three-quarters.

Favourite Kasbah Bliss proved a disappointment by only finishing fourth to become the second odds-on shot to be beaten on the day.

Trainer Paul Nicholls had intended to aim Big Buck's at the Cheltenham Gold Cup this year but a final flight error in the Hennessy at Newbury in November brought a change of plan and a return to smaller obstacles.

Walsh said: “This horse has got a huge engine but when I got to Barry I thought I'd got there too soon again.” Nicholls, bringing up a double on the day, said: “I was very confident we had him at his peak. Making a mistake at the last probably wouldn't have done him too much harm as he had something to aim at.”

There was another shock in the day's first Grade 1 contest when hot favourite Voy Por Ustedes could only finish second to 6-1 shot Imperial Commander in the Ryanair Chase.

The winner, who was giving trainer Nigel Twiston-Davies his second success at this week's Festival following Tricky Trickster's win yesterday, suffered an injury when disappointing in the King George VI Chase at Kempton on Boxing Day, but returned to top form to win by two lengths under jockey Paddy Brennan.

Robert Thornton was passed fit to ride Voy Por Ustedes following a fall yesterday but the eight-year-old, sent off the 4-5 favourite in a bid to win a third different race at the Cheltenham Festival, made two serious errors but still battled back to be in contention at the final fence.

An elated Brennan, winning his first race at the Festival, said: “This is better than riding 40 winners.

“When you've ridden a winner here you feel like you're the only person in the world. I'm so happy.”

Earlier, Aidan Coleman also rode his first Festival winner when partnering Kayf Aramis to victory in the Pertemps Final for trainer Venetia William while Timmy Murphy enjoyed an armchair ride on the Nicholls-trained Chapoturgeon to win the Jewson Novices' Handicap Chase by nine lengths.