Kerry Lee's Happy Diva claimed the BetVictor Gold Cup at Cheltenham.
The eight-year-old 14-1 shot and jockey Richard Patrick were brought down in this race last year, but held on to see off Brelan D'as (20-1) by a neck.
Favourite Slate House started badly but was challenging in a group of four only to fall at the penultimate fence.
Meanwhile at Punchestown, Willie Mullins won a 10th Morgiana Hurdle as 7-1 Saldier beat Petit Mouchoir (16-1) by a length and a half.
In a race expected to provide early clues to the Champion Hurdle at March's Cheltenham Festival, Mullins had three of the five runners but his 2-5 favourite Klassical Dream was two and a half lengths back in third.
Henry de Bromhead's Petit Mouchoir, ridden by Rachael Blackmore, led by more than two lengths at halfway but was reeled in by Saldier, who took the lead jumping the last.
Happy Diva is the first mare to win the coveted Cheltenham race for horses aged four and over, first run in 1960, since Lady Cricket in 2000.
Lee, who is only the third female trainer to triumph in the race, said: "It's a tough job and you do sometimes wonder why you do it, but days like this are what it's all about."
Cornelius Lysaght, BBC racing correspondent:
There's nothing quite like righting a sporting 'wrong', and that's what Happy Diva and team achieved gloriously as the mare narrowly held off Brelan D'As.
Twelve months previously, Kerry Lee, Richard Patrick and owner Will Roseff were left wondering what might have been after Happy Diva was brought down late on when going pretty well.
This time, Lee insisted her heart wasn't in her mouth when the horse raced through the closing stages - mine certainly was - but all was well.
Slate House moved strongly into a challenging position, and was there with a shout, when falling at the second last.