Joe Farrell, ridden by Adam Wedge, held off the challenge of Ballyoptic and Tom Bellamy to win the Scottish Grand National after a photo finish.
The 33-1 chance led approaching the last fence in the four-mile test at Ayr but then made a slight error.
It allowed Ballyoptic (9-1) to move up and challenge but Joe Farrell just managed to hold on.
It was a first winner in Scotland for Welsh trainer Rebecca Curtis who also part-owns the horse.
Third went to Vintage Clouds (12-1) ridden by Danny Cook, while Noel Fehily and Doing Fine (12-1) were fourth.
The 7-1 favourite Fagan - trained by Gordon Elliott, who had been hoping to complete a Grand National treble, having won last weekend's Aintree showpiece and the Irish equivalent earlier this month - never really featured.
Vicenti, trained by Paul Nicholls and ridden by Sam Twiston-Davies, had been chasing a hat-trick of wins in the race and did challenge briefly but faded out of contention late on.
It has been a tough campaign for Curtis, who was winning just her ninth race of the season and has blamed her recent lack of success on a number of factors, including horses being removed from her charge and domestic problems.
"We've had a difficult season. I thought it was a big ask. He's still a novice for a big race like that, but I knew he'd stay all day," said the Pembrokeshire-based trainer.
"He wanted a bit better ground, so that was brilliant. He idled at the end in front. If he'd have got beaten on the line, I'd have been gutted.
"Watching it, I thought he had held on - I hoped he had.
"I own a quarter of him. I bought him quite cheaply out of John Ferguson's sale. He had broken down on both his front legs. I took a chance with him and thankfully he's won a big race. It's all paid off."
Horse racing correspondent Cornelius Lysaght
A potentially very significant success for Rebecca Curtis, who claimed just her ninth win of a disappointing season - she had 30 last time and 45 as recently as three years ago.
Winning part-owner Mark Sherwood suggested they run to try to put the Curtis team back on the map, which is exactly what Joe Farrell and Adam Wedge did in the second breathless finish to a Grand National in a week, after Tiger Roll and Pleasant Company at Aintree.