Kim Bailey & Mat Nicholls caused a 40/1 shock in Thursday's opening Ryanair Mares' Novices' Hurdle with White Noise.
The six-year-old daughter of Kingston Hill was ridden prominently by Tom Bellamy and saw off all rivals up the hill as even-money favourite Bambino Fever proved a major disappointment.
Oldschool Outlaw (15/2) emerged from the chasing pack in the JP McManus colours to lay down a late challenge, but White Noise found plenty for pressure to run out a convincing winner over the Gordon Elliott-trained mare.
Place De La Nation was third at 28/1 to complete an early Placepot buster.
13:20 Cheltenham - Ryanair Mares' Novices' Hurdle result
1st WHITE NOISE 40/1
2nd Oldschool Outlaw 15/2
3rd Place De La Nation 28/1
Winning rider Tom Bellamy told ITV Racing: “I can’t believe it. I’ve waited my whole life for this day.
“A great performance from a really likeable filly, delighted for the team at home who have had a really good season.
“I used to bunk off school to come watch the Cheltenham Festival and I can’t believe I’m now here.”
Nicholls said: “That’s pretty special. She has just improved all season. We thought long and hard about whether we should come here or not, but with the race being on the New course it was a bit of a stiffer test for her. I’m lost for words at the moment, but she is very good.
“She has improved all season, but we thought she would be a three mile chaser when we bought her. Tom was absolutely brilliant at the start.
“The sad thing from this week’s racing is that the starts are being a big thing. Tom Bellamy at the start was incredible. He has lined up on the outside and before you know it he is in front, and I’m not quite sure how he has managed it, but it has made a big difference.
“I thought we might be in the first six, but I would be lying if I thought she would win. I couldn’t why David Pipe’s horse (Kingston Queen) was 16/1 and we were 40/1, so on form I thought we had a chance and I knew the stiff two miles would be up our street.
“She has just been in great order all season.”
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And as for Bailey, who has masterminded the Gold Cup triumph of Master Oats and Champion Hurdle victory of Alderbrook at the meeting, he was equally proud of White Noise, which was also a first victory at the meeting for long-standing owner John Perriss.
Bailey added: “She was 80/1 this morning and Oli Bell tipped her up. She has got really good form and we thought we would beat the horse that beat us last time (Kingston Queen) as two miles was going to suit her better.
“Tom gave her a breather at the right time and I’m thrilled for John as he has been with me for thirty eight years and that is his first Cheltenham winner.
“This is a great result for the whole yard and everyone involved with it.”