Bluesea Cracker, trained by James Motherway, landed an incident-packed renewal of the Powers Whiskey Irish Grand National at Fairyhouse.
There were plenty of casualties in the three-mile-five-furlong contest, including favourite Saddlers Storm, leading fancy Telenor and British raider Double Dizzy.
Bluesea Cracker (25-1) was well to the fore as the field rounded the turn for home for the final time. And although she began to tire on the run-in, Andrew McNamara's mount had enough in reserve to repel the challenge of Oscar Time by four and a half lengths.
Whatuthink was third, with Cheltenham cross-country winner A New Story fourth.
It was the biggest success in the career of Cork-based Motherway - and the trainer's first over fences this season.
Bluesea Cracker had finished second to Ballytrim on her latest appearance at Naas in March but had won a Grade Two as a novice at Limerick in April last year, the only other time she had been partnered by McNamara.
William Hill make the mare 33-1 for next year's Grand National at Aintree.
A delighted James Motherway said: 'We wondered if she would get home on the soft ground - I just did not know. She has been fantastic for us over the last four years.'
Andrew McNamara added: 'I jumped off and got a lovely position on the inner. At the second fence away from the stand she met it wrong and hit it a belt - she did really well to recover.'
'In the straight I gave her a squeeze and she quickened up well.
Going to the last she ran around a bit and I dropped my stick trying to get two hands on the rein.'
