Merigo became the first horse for 27 years to win the Scottish Grand National twice with a courageous effort in the marathon handicap chase at Ayr.
While Androma landed back-to-back victories in 1984 and 1985, Merigo was reclaiming his crown after finishing second last year.
Merigo answered veteran jockey Timmy Murphy’s every call to hold Auroras Encore in a thrilling duel over the last three fences in the straight.
The 15-2 winner was ridden by Murphy for his father-in-law owner Raymond Anderson Green.
“It’s great that he’s made history by being the first horse to win it, finish second and then come back and win it a second time,” trainer Andrew Parker said.
“He loves Ayr, he loves the sun on his back. He’s just a different horse here than anywhere else.
“I thought we might be struggling, but one thing he has got is the heart of a lion. Timmy said he’s losing his pace but he’s got heart.”
Anderson Green said he would like to see Merigo come back in 2013 to try to win the race for a third time.
“To win it once is dreamland, to come back and do it again – words can’t describe it. It means everything to me to win this race,” he said.
“Timmy gave him a fantastic ride. The horse doesn’t like getting beaten. He is all guts and just grinds it out.
“We’ll have to get him lined up to try to win for a third time next year, but I think come 12 months’ time he may need a bit softer ground.”
There was a slight tempering of celebrations for Murphy who he was banned for four days for using his whip above the permitted limit.