Frost had steered Frodon to three wins earlier in the season
Jockey Bryony Frost made Cheltenham Festival history as she became the first woman to ride a top-level Grade One winner over jumps at the meeting when Frodon landed an emotional triumph in the Ryanair Chase.
Frost, 23, the daughter of Grand National-winning jockey Jimmy, punched the air with delight after victory on the 9-2 chance, trained by Paul Nicholls.
"He's Pegasus," said a tearful Frost after her bold-jumping mount finished ahead of Aso and Road To Respect.
As the jockey and her mount returned to a rapturous reception in the winner's enclosure, 10-time champion trainer Nicholls said it was "one of the best days ever".
Aso (33-1) kept on for second, with Road To Respect (9-2) third.
It was Frost's second victory at the showpiece meeting after winning the Foxhunter Chase on Pacha Du Polder in 2017.
She follows in the path of the now-retired Katie Walsh who won a Grade One race at the Festival last year when Relegate came home first in the Champion Bumper, which is a flat race under National Hunt rules.
"We have climbed a mountain to get to this," Frost told BBC Radio 5 Live. "It's incredible and I'll enjoy every minute of it."
'He deserves every high five, pat and carrot'
Frost and Frodon have built a perfect partnership over the last two seasons and they were smoothly into their rhythm at the front from the start of the race over two miles and five furlongs.
The seven-year-old gelding had been considered for a tilt at the longer Cheltenham Gold Cup on Friday, but it was felt he would be better suited by this contest on rain-softened ground, and he relished the trip.
Frost is from Buckfastleigh in south Devon
Sub Lieutenant and Road To Respect vied for the lead at one stage, but it was only 33-1 outsider Aso, ridden by Charlie Deutsch for trainer Venetia Williams, who could stay with the leader before having to settle for second.
Frost, who was landing her second Grade One win after victory in the Kauto Star Novices' Chase at Kempton in December on Black Corton, said: "He's the most incredible battler!
"He travelled, my God he jumped, and the moment he got overtaken two out, most horses would have quit. He grabbed me by the hands and said don't you dare give up. He's unbelievable.
"He deserves every single high five, pat and carrot."
Frost at forefront of racing's new generation
Frost is one of a new generation of female jockeys marking their mark in a sport where women often compete against men on equal terms.
Lizzie Kelly, who became the first female jockey to win a Grade One jumps race in Britain in December 2015, is another.
And she joined Frost on the 2019 roll of honour later on Thursday when Siruh Du Lac claimed the Stable Plate.
The 9-2 chance had to battle all the way to the line to hold off the challenge of favourite Janika.
Thursday's double followed the first Festival success for Rachael Blackmore, who is bidding to become the first female champion jockey in Ireland in a title race which ends in May, who won on Tuesday on A Plus Tard.
BBC horse racing commentator John Hunt reflects on a memorable day's racing at the Festival'We're so proud of Bryony'
Frost has bounced back after suffering serious injuries in a fall last year which ruled her out for three months.
She was joined by her family for the celebrations on Thursday, including one of her brothers Hadden who flew back from the US for the race.
"Incredible, so proud of her. She and the horse did not miss a beat out there," said her father Jimmy.
"We walked the course this morning together and she took it all in, as she showed in the race."
Frost said Frodon had 'made her dreams come true'
In a pre-Festival column for BBC Sport, Frost described her partnership with Frodon, a Cheltenham specialist who has won five times at the Gloucestershire track.
"He's numb in his braveness. He's more competitive and braver than I am. He wants it. He knows his races and courses so well," she said.
"If he was a kid who went to school, he would definitely come out with A stars.
"When he was younger, he was quite bullish and a know-it-all. This year, we have really clicked, we have just found this wave we are riding on together.
"I know for a fact he will offer me 100% of himself, and I will give it right back. 'Frod' is the man. It's a privilege to be with him."
'Racing's new Frankie Dettori' - analysis
by BBC horse racing correspondent Cornelius Lysaght
For the sport of horse racing, the feature steeplechase of the day will rate as one of the most important races of the season partly, of course, for a fine equine performance, but even more for success of the jockey dubbed 'racing's new Frankie Dettori'.
Like Dettori, Bryony Frost has everything that's required to be a star in the wider modern sporting world: consummate skills, obviously, but also a communication ability to match - to say the irrepressible Frost has both in bundles doesn't entirely do her justice.
There is no doubt that this talented, interesting, bubbly character - the crowds adore her - is a classic poster-person and role model about whom more and more people are sure to be hearing.
Television presenter and author Clare Balding praised the achievements of Frost and KellyFormer GB hockey player Sam Quek said both Frost and Lizzie Kelly are superb role models
