Colman Sweeney gave Salsify a peach of a ride to win the Christie's Foxhunter Chase.
The 7/1 chance was ridden with huge confidence by the top amateur, settled right out the back as Picaroon set a blistering pace that forced several into jumping errors.
Sweeney was still fully 10 lengths off the lead - now in the hands of Oscar Delta - turning into the home straight, but had the fancied Chapoturgeon (3/1f) for company.
The latter had been given a similarly patient ride by Jack Barber and the pair swooped at the final fence to land upsides the mare.
And in the dash for the line it was Colman who held the upper hand, getting on top close home to win by a length, the two drawing 11 lengths clear of Oscar Delta (28/1) in third.
Trainer Rodger Sweeney said: "He gave him a great ride and to have a winner at Cheltenham is unreal.
"I'm delighted for everybody. I know he was going along easily but so was the favourite.
"It's nice to see him come back and win his race. It's a dream come true."
Colman Sweeney added: "I had to lose a lot of weight before Christmas to get to ride him and I got down to 11st 5lb on New Year's Eve - it's been worth it.
"He disappointed at Thurles in January but he still had a lot of condition on him then. He won well the last day and this is just unbelievable."