Mountainous won a thrilling renewal of the Coral Welsh Grand National as Richard Lee's charge beat off the Paul Nicholls' pair of Hawkes Point and Tidal Bay at Chepstow.
The 20-1 shot battled on bravely in the hands of Paul Moloney to give Lee his second success in this race in three years after Le Beau Bai in 2011.
The winner's stablemate Knock A Hand set the pace with Highland Lodge before the marathon began in earnest over the last five fences in the straight.
The result could have gone any way at the last but it was Mountainous who prevailed by a head from Hawkes Point (14-1) with the gallant top weight Tidal Bay (10-1) half a length away in third.
One In A Milan (50-1) was fourth and Merry King (9-1) fifth.
Moloney told Channel 4 Racing: "Fair play to the trainer, he knows how to get one ready.
"It was great to get the ride and thanks to my agent for getting it for me.
"I'd seen a couple of his replays and he tends to idle in front, so I didn't want to get there too soon."
Lee said: "This is just as good as the first time.
"I couldn't believe how well he was going. Paul gave him an intelligent ride and got a breather into him. I was also delighted with the way my other horse, Knock A Hand, ran.
"Mountainous has always been a nice horse. From the moment he came into our yard as a five-year-old, I said he was a Welsh National horse. I love my staying chases."