Willie Mullins claimed the Weatherbys Champion Bumper for an eighth time courtesy of Briar Hill.
The five-year-old (25-1) trounced his rivals under Ruby Walsh with a withering late run around the outside of the field.
Mullins was securing his fifth winner at this year's Cheltenham Festival, and Walsh his fourth.
Runner-up Regal Encore (7-1 joint-favourite) fleetingly looked the biggest danger along the straight, but the Graham Wylie-owned Briar Hill bounded up the hill to score by seven lengths.
Golantilla finished third for the Tony Martin team.
Walsh said: "I got a bad break and got knocked down, but it worked out.
"When I gave him a smack he took off - he was very impressive.
"He's no 'flash harry' at home but you don't mind when they do it on a racecourse.
"It was a bit of a surprise but a nice surprise. It looked a strong enough race on paper, and he's somewhere related to Boston Bob and we have always classed him as a chaser down the line rather than a bumper horse.
"I think all the championship races here are won by good horses."
Briar Hill is next season likely to be campaign as a staying hurdler.
Mullins, who had three runners in the race, added: "I thought I had a chance, but I didn't think it would be with this one.
"If you rated the three horses, he would probably have been bottom of them all, so it's a nice surprise.
"We'll think about Punchestown. He'll go down the novice hurdling route and I see him being an Albert Bartlett horse."
Regal Encore's trainer Anthony Honeyball said with a smile: "I'm pleased for Ruby and Willie - they really needed it.
"I'm delighted with the run but he's still a bit keen and needs to be held up.
"Hopefully in time we'll be able to ride him a bit further up with the pace."